[PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Egbert Eich]

Despite the many attempts to fix the issue with noisy hotplug interrupt lines
we are still seeing systems that suffer from this:
Recently we encountered a rather large scale installation of Q35 systems
which was hit by this issue rather severely: It seemed as if not all machines
of the same model were hit equally bad, in the worst cased hotplug
interrupt noise caused several 1000 interrupts / s. Those machines would not
even boot, instead the interrupt handler and the scheduled workers would keep
the CPU  busy that eventually the watchdog would kick in and issue an NMI.
Other machines only received severa 10s to 100s of interrupts per sec - those
machines would run properly - just with an excessive system load.
More thorough investigations seemed to indicate that this condition
only happen at certain video modes.

On another system - a laptop - a hotplug interrupt 'storm' occurred when 
it was charging and the batteries were at certain charge levels. While 
the system was still running fine its load was high enough that the user
noticed from the fan noise that a problem existed.
The latter system had a Sandybridge chipset, thus a totally different 
generation from the former.

All those cases seemed to have been caused by cross talk on badly routed 
hotplug signal lines (or voltage instabilities).
This led to the conclusion that instead of trying to work around these
'storms' for each individual system, there should be a generic way to detect 
such a condition and take appropriate action:

This patch series implements a hotplug 'storm' detection, disables the
respective interrupt for the hotplug pin when this condition is detected
and reverts to periodic output polling on the affected connector.
After a grace period of 2 minutes it will reenable hotplug on the affected
line. This will take care of cases in which this condition is only temporary.
Should the 'storm' condtion persist, this cycle will start over again.

To implement this some rearrangements in the code were required:
- The interrupt status bit which signals a hotplug needed to be recorded
  for each connector.
- The interrupt enable functions needed to be separate, also they need 
  to be able to enable interrupts for each hotplug line independently.


Egbert Eich (8):
  drm/i915: Remove pch_rq_mask from struct drm_i915_private.
  drm/i915: Set hotplug_supported_flag for all chipset generations.
  drm/i915: Add hpd status bit to struct intel_connector.
  drm/i915: Add Hotplug IRQ Storm detection.
  drm/i915: Move hotplug interrupt enable for i915/i965/valleyview into
    a separate function.
  drm/i915: Only enable hotplug irq when needed on Ironlake and later
    chips.
  drm/i915: When detecting a hotplug IRQ storm disable respective IRQs.
  drm/i915: Add Reenable Timer to turn Hotplug Detection back on.

 drivers/gpu/drm/i915/i915_drv.h   |    7 +-
 drivers/gpu/drm/i915/i915_irq.c   |  475 +++++++++++++++++++++++++++----------
 drivers/gpu/drm/i915/intel_crt.c  |    3 +-
 drivers/gpu/drm/i915/intel_dp.c   |    5 +-
 drivers/gpu/drm/i915/intel_drv.h  |   11 +
 drivers/gpu/drm/i915/intel_hdmi.c |    5 +-
 drivers/gpu/drm/i915/intel_sdvo.c |   23 +-
 7 files changed, 383 insertions(+), 146 deletions(-)

-- 
1.7.7

[PATCH 1/8] drm/i915: Remove pch_rq_mask from struct drm_i915_private.

[Egbert Eich]

This variable is only used locally in the irq postinstall
functions for ivybridge and ironlake.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    1 -
 drivers/gpu/drm/i915/i915_irq.c |   10 ++++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ed30595..eeaf2a8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -665,7 +665,6 @@ typedef struct drm_i915_private {
 	u32 pipestat[2];
 	u32 irq_mask;
 	u32 gt_irq_mask;
-	u32 pch_irq_mask;
 
 	u32 hotplug_supported_mask;
 	struct work_struct hotplug_work;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2220dec..bb5e6d8 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1857,6 +1857,7 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
 			   DE_PLANEA_FLIP_DONE | DE_PLANEB_FLIP_DONE;
 	u32 render_irqs;
 	u32 hotplug_mask;
+	u32 pch_irq_mask;
 
 	dev_priv->irq_mask = ~display_mask;
 
@@ -1897,10 +1898,10 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
 				SDE_AUX_MASK);
 	}
 
-	dev_priv->pch_irq_mask = ~hotplug_mask;
+	pch_irq_mask = ~hotplug_mask;
 
 	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
-	I915_WRITE(SDEIMR, dev_priv->pch_irq_mask);
+	I915_WRITE(SDEIMR, pch_irq_mask);
 	I915_WRITE(SDEIER, hotplug_mask);
 	POSTING_READ(SDEIER);
 
@@ -1927,6 +1928,7 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
 		DE_PLANEA_FLIP_DONE_IVB;
 	u32 render_irqs;
 	u32 hotplug_mask;
+	u32 pch_irq_mask;
 
 	dev_priv->irq_mask = ~display_mask;
 
@@ -1954,10 +1956,10 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
 			SDE_PORTB_HOTPLUG_CPT |
 			SDE_PORTC_HOTPLUG_CPT |
 			SDE_PORTD_HOTPLUG_CPT);
-	dev_priv->pch_irq_mask = ~hotplug_mask;
+	pch_irq_mask = ~hotplug_mask;
 
 	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
-	I915_WRITE(SDEIMR, dev_priv->pch_irq_mask);
+	I915_WRITE(SDEIMR, pch_irq_mask);
 	I915_WRITE(SDEIER, hotplug_mask);
 	POSTING_READ(SDEIER);
 
-- 
1.7.7

[PATCH 2/8] drm/i915: Set hotplug_supported_flag for all chipset generations.

[Egbert Eich]

So far the hotplug_supported_mask in the struct drm_i915_private
is only used for pre-Ironlake chipsets.
This patch sets up the correct value for all generations.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h   |    4 ++
 drivers/gpu/drm/i915/i915_irq.c   |   71 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_crt.c  |    2 +-
 drivers/gpu/drm/i915/intel_dp.c   |    4 +--
 drivers/gpu/drm/i915/intel_hdmi.c |    4 +--
 drivers/gpu/drm/i915/intel_sdvo.c |   12 +------
 6 files changed, 79 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index eeaf2a8..d7ad677 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1322,6 +1322,10 @@ extern void intel_irq_init(struct drm_device *dev);
 extern void intel_gt_init(struct drm_device *dev);
 extern void intel_gt_reset(struct drm_device *dev);
 
+extern u32 intel_crt_hotplug_int_status(struct drm_device *dev);
+extern u32 intel_sdvo_hotplug_int_status(struct drm_device *dev, bool is_sdvo_b);
+extern u32 intel_hotplug_int_status(struct drm_device *dev, enum port port);
+
 void i915_error_state_free(struct kref *error_ref);
 
 void
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index bb5e6d8..c0e302e 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2765,3 +2765,74 @@ void intel_irq_init(struct drm_device *dev)
 		dev->driver->disable_vblank = i915_disable_vblank;
 	}
 }
+
+u32 intel_hotplug_int_status(struct drm_device *dev, enum port port)
+{
+	/* SDVO is treated separately */
+	if (IS_IVYBRIDGE(dev) ||
+	    IS_HASWELL(dev) ||
+	    (HAS_PCH_SPLIT(dev) && HAS_PCH_CPT(dev))) {
+		switch (port) {
+		case PORT_B:
+			return SDE_PORTB_HOTPLUG_CPT;
+		case PORT_C:
+			return SDE_PORTC_HOTPLUG_CPT;
+		case PORT_D:
+			return SDE_PORTD_HOTPLUG_CPT;
+		default:
+			BUG();
+		}
+	} else if (HAS_PCH_SPLIT(dev)) { /* ! HAS_PCH_CPT(dev) */
+		switch (port) {
+		case PORT_B:
+			return SDE_PORTB_HOTPLUG;
+		case PORT_C:
+			return SDE_PORTC_HOTPLUG;
+		case PORT_D:
+			return SDE_PORTD_HOTPLUG;
+		default:
+			BUG();
+		}
+	} else {
+		switch (port) {
+		case PORT_B:
+			return HDMIB_HOTPLUG_INT_STATUS; /* same as PDB_HOTPLUG_INT_STATUS */
+		case PORT_C:
+			return HDMIC_HOTPLUG_INT_STATUS; /* same as PDB_HOTPLUG_INT_STATUS */
+		case PORT_D:
+			return HDMID_HOTPLUG_INT_STATUS; /* same as PDB_HOTPLUG_INT_STATUS */
+		default:
+			BUG();
+		}
+	}
+	return 0;
+}
+
+u32 intel_crt_hotplug_int_status(struct drm_device *dev)
+{
+	if (IS_IVYBRIDGE(dev) ||
+	    IS_HASWELL(dev) ||
+	    (HAS_PCH_SPLIT(dev) && HAS_PCH_CPT(dev))) {
+		return SDE_CRT_HOTPLUG_CPT;
+	} else if (HAS_PCH_SPLIT(dev)) { /* ! HAS_PCH_CPT(dev) */
+		return SDE_CRT_HOTPLUG;
+	} else {
+		return CRT_HOTPLUG_INT_STATUS;
+	}
+	return 0;
+}
+
+u32 intel_sdvo_hotplug_int_status(struct drm_device *dev, bool is_sdvo_b)
+{
+	if (IS_G4X(dev)) {
+		return is_sdvo_b ?
+			SDVOB_HOTPLUG_INT_STATUS_G4X : SDVOC_HOTPLUG_INT_STATUS_G4X;
+	} else if (IS_GEN4(dev)) {
+		return is_sdvo_b ?
+			SDVOB_HOTPLUG_INT_STATUS_I965 : SDVOC_HOTPLUG_INT_STATUS_I965;
+	} else {
+		return is_sdvo_b ?
+			SDVOB_HOTPLUG_INT_STATUS_I915 : SDVOC_HOTPLUG_INT_STATUS_I915;
+	}
+	return 0;
+}
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index fe20bf7..0cd9ff0 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -797,7 +797,7 @@ void intel_crt_init(struct drm_device *dev)
 	 */
 	crt->force_hotplug_required = 0;
 
-	dev_priv->hotplug_supported_mask |= CRT_HOTPLUG_INT_STATUS;
+	dev_priv->hotplug_supported_mask |= intel_crt_hotplug_int_status(dev);
 
 	/*
 	 * TODO: find a proper way to discover whether we need to set the
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d76258d..1946b5b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2754,21 +2754,19 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 		name = "DPDDC-A";
 		break;
 	case PORT_B:
-		dev_priv->hotplug_supported_mask |= DPB_HOTPLUG_INT_STATUS;
 		name = "DPDDC-B";
 		break;
 	case PORT_C:
-		dev_priv->hotplug_supported_mask |= DPC_HOTPLUG_INT_STATUS;
 		name = "DPDDC-C";
 		break;
 	case PORT_D:
-		dev_priv->hotplug_supported_mask |= DPD_HOTPLUG_INT_STATUS;
 		name = "DPDDC-D";
 		break;
 	default:
 		WARN(1, "Invalid port %c\n", port_name(port));
 		break;
 	}
+	dev_priv->hotplug_supported_mask |= intel_hotplug_int_status(dev, port);
 
 	if (is_edp(intel_dp))
 		intel_dp_init_panel_power_sequencer(dev, intel_dp);
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 2ee9821..d20f9ff 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -980,21 +980,19 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
 	switch (port) {
 	case PORT_B:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPB;
-		dev_priv->hotplug_supported_mask |= HDMIB_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_C:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPC;
-		dev_priv->hotplug_supported_mask |= HDMIC_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_D:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPD;
-		dev_priv->hotplug_supported_mask |= HDMID_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_A:
 		/* Internal port only for eDP. */
 	default:
 		BUG();
 	}
+	dev_priv->hotplug_supported_mask |= intel_hotplug_int_status(dev, port);
 
 	if (!HAS_PCH_SPLIT(dev)) {
 		intel_hdmi->write_infoframe = g4x_write_infoframe;
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 0e03985..567846e 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -2727,17 +2727,7 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
 		}
 	}
 
-	hotplug_mask = 0;
-	if (IS_G4X(dev)) {
-		hotplug_mask = intel_sdvo->is_sdvob ?
-			SDVOB_HOTPLUG_INT_STATUS_G4X : SDVOC_HOTPLUG_INT_STATUS_G4X;
-	} else if (IS_GEN4(dev)) {
-		hotplug_mask = intel_sdvo->is_sdvob ?
-			SDVOB_HOTPLUG_INT_STATUS_I965 : SDVOC_HOTPLUG_INT_STATUS_I965;
-	} else {
-		hotplug_mask = intel_sdvo->is_sdvob ?
-			SDVOB_HOTPLUG_INT_STATUS_I915 : SDVOC_HOTPLUG_INT_STATUS_I915;
-	}
+	hotplug_mask = intel_sdvo_hotplug_int_status(dev, intel_sdvo->is_sdvob);
 
 	drm_encoder_helper_add(&intel_encoder->base, &intel_sdvo_helper_funcs);
 
-- 
1.7.7

[PATCH 3/8] drm/i915: Add hpd status bit to struct intel_connector.

[Egbert Eich]

To be able to map an HPD interrupt to a connector add the
hpd status bit to the intel_connector structure.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/intel_crt.c  |    3 ++-
 drivers/gpu/drm/i915/intel_dp.c   |    3 ++-
 drivers/gpu/drm/i915/intel_drv.h  |    3 +++
 drivers/gpu/drm/i915/intel_hdmi.c |    3 ++-
 drivers/gpu/drm/i915/intel_sdvo.c |   11 ++++++++++-
 5 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 0cd9ff0..75298ce 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -797,7 +797,8 @@ void intel_crt_init(struct drm_device *dev)
 	 */
 	crt->force_hotplug_required = 0;
 
-	dev_priv->hotplug_supported_mask |= intel_crt_hotplug_int_status(dev);
+	intel_connector->hpd_status_bit = intel_crt_hotplug_int_status(dev);
+	dev_priv->hotplug_supported_mask |= intel_connector->hpd_status_bit;
 
 	/*
 	 * TODO: find a proper way to discover whether we need to set the
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 1946b5b..b97eb76 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2766,7 +2766,8 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 		WARN(1, "Invalid port %c\n", port_name(port));
 		break;
 	}
-	dev_priv->hotplug_supported_mask |= intel_hotplug_int_status(dev, port);
+	intel_connector->hpd_status_bit = intel_hotplug_int_status(dev, port);
+	dev_priv->hotplug_supported_mask |= intel_connector->hpd_status_bit;
 
 	if (is_edp(intel_dp))
 		intel_dp_init_panel_power_sequencer(dev, intel_dp);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 8a1bd4a..a251036 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -191,6 +191,9 @@ struct intel_connector {
 
 	/* Cached EDID for eDP and LVDS. May hold ERR_PTR for invalid EDID. */
 	struct edid *edid;
+
+	/* hpd status bit for this connector */
+	u32 hpd_status_bit;
 };
 
 struct intel_crtc {
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index d20f9ff..9099b6dc 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -992,7 +992,8 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
 	default:
 		BUG();
 	}
-	dev_priv->hotplug_supported_mask |= intel_hotplug_int_status(dev, port);
+	intel_connector->hpd_status_bit = intel_hotplug_int_status(dev, port);
+	dev_priv->hotplug_supported_mask |= intel_connector->hpd_status_bit;
 
 	if (!HAS_PCH_SPLIT(dev)) {
 		intel_hdmi->write_infoframe = g4x_write_infoframe;
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 567846e..c99bb9d 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -2697,6 +2697,7 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_encoder *intel_encoder;
 	struct intel_sdvo *intel_sdvo;
+	struct drm_connector *connector;
 	u32 hotplug_mask;
 	int i;
 
@@ -2749,8 +2750,16 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
 	/* Only enable the hotplug irq if we need it, to work around noisy
 	 * hotplug lines.
 	 */
-	if (intel_sdvo->hotplug_active)
+	if (intel_sdvo->hotplug_active) {
 		dev_priv->hotplug_supported_mask |= hotplug_mask;
+		list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+			struct intel_connector *intel_connector = to_intel_connector(connector);
+			if (intel_connector->encoder == intel_encoder) {
+				intel_connector->hpd_status_bit = hotplug_mask;
+				break;
+			}
+		}
+	}
 
 	intel_sdvo_select_ddc_bus(dev_priv, intel_sdvo, sdvo_reg);
 
-- 
1.7.7

[PATCH 4/8] drm/i915: Add Hotplug IRQ Storm detection.

[Egbert Eich]

Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
fires more than 5 times / sec).
Mask out this specific interrupt and revert to polling on the associated
output.
Rationale:
Despite of the many attempts to fix the problem with noisy hotplug
interrupt lines we are still seeing systems which have issues:
Once cause of noise seems to be bad routing of the hotplug line
on the board: cross talk from other signals seems to cause erronous
hotplug interrupts. This has been documented as an erratum for the
the i945GM chipset and thus hotplug support was disabled for this
chipset model but others seem to have this problem, too.

We have seen this issue on a G35 motherboard for example:
Even different motherboards of the same model seem to behave
differently: while some only see only around 10-100 interrupts/s
others seem to see 5k or more.
We've also observed a dependency on the selected video mode.

Also on certain laptops interrupt noise seems to occur duing
battery charging when the battery is at a certain charge levels.

Thus we add a simple algorithm here that detects an 'interrupt storm'
condition.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c  |   74 ++++++++++++++++++++++++++++++++------
 drivers/gpu/drm/i915/intel_drv.h |    4 ++
 2 files changed, 67 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index c0e302e..4e75df0 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -285,11 +285,24 @@ static void i915_hotplug_work_func(struct work_struct *work)
 						    hotplug_work);
 	struct drm_device *dev = dev_priv->dev;
 	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct drm_connector *connector;
 	struct intel_encoder *encoder;
+	unsigned long irqflags;
 
 	mutex_lock(&mode_config->mutex);
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		struct intel_connector *intel_connector = to_intel_connector(connector);
+		if (intel_connector->hpd_mark_disabled) {
+			intel_connector->hpd_mark_disabled = 0;
+			connector->polled = DRM_CONNECTOR_POLL_CONNECT
+				 | DRM_CONNECTOR_POLL_DISCONNECT;
+		}
+	}
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
 	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
 		if (encoder->hot_plug)
 			encoder->hot_plug(encoder);
@@ -300,6 +313,36 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	drm_helper_hpd_irq_event(dev);
 }
 
+static inline void hotplug_irq_storm_detect(struct drm_device *dev, u32 hotplug_trigger)
+{
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct drm_connector *connector;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		struct intel_connector *intel_connector = to_intel_connector(connector);
+
+		if (hotplug_trigger & intel_connector->hpd_status_bit) {
+			if (jiffies > (intel_connector->last_hpd_jiffies + msecs_to_jiffies(1000)) ||
+			    jiffies < intel_connector->last_hpd_jiffies) {
+				intel_connector->last_hpd_jiffies = jiffies;
+				intel_connector->hpd_cnt = 0;
+			} else if (intel_connector->hpd_cnt > 5) {
+				dev_priv->hotplug_supported_mask &= ~intel_connector->hpd_status_bit;
+				intel_connector->hpd_mark_disabled = 1;
+				pr_warn("HPD interrupt storm on connector %s disabling\n",
+					 drm_get_connector_name(connector));
+			} else
+				intel_connector->hpd_cnt++;
+		}
+	}
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
 /* defined intel_pm.c */
 extern spinlock_t mchdev_lock;
 
@@ -579,13 +622,14 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
-
+			u32 hotplug_trigger = hotplug_status & dev_priv->hotplug_supported_mask;
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
@@ -609,10 +653,12 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & dev_priv->hotplug_supported_mask;
 
-	if (pch_iir & SDE_HOTPLUG_MASK)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK) >>
@@ -652,10 +698,12 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & dev_priv->hotplug_supported_mask;
 
-	if (pch_iir & SDE_HOTPLUG_MASK_CPT)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
@@ -2368,13 +2416,15 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 		if ((I915_HAS_HOTPLUG(dev)) &&
 		    (iir & I915_DISPLAY_PORT_INTERRUPT)) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & dev_priv->hotplug_supported_mask;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			POSTING_READ(PORT_HOTPLUG_STAT);
 		}
@@ -2606,13 +2656,15 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & dev_priv->hotplug_supported_mask;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index a251036..2d003d9 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -194,6 +194,10 @@ struct intel_connector {
 
 	/* hpd status bit for this connector */
 	u32 hpd_status_bit;
+	/* bookkeeping for irq storm detection */
+	int hpd_cnt;
+	unsigned long last_hpd_jiffies;
+	bool hpd_mark_disabled;
 };
 
 struct intel_crtc {
-- 
1.7.7

[PATCH 5/8] drm/i915: Move hotplug interrupt enable for i915/i965/valleyview into a separate function.

[Egbert Eich]

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |  178 ++++++++++++++++++++++----------------
 1 files changed, 103 insertions(+), 75 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 4e75df0..356472f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -567,6 +567,32 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
 	queue_work(dev_priv->wq, &dev_priv->rps.work);
 }
 
+static void valleyview_enable_hotplug_irq(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
+	hotplug_en &= ~(HDMIB_HOTPLUG_INT_EN | HDMIC_HOTPLUG_INT_EN |
+			HDMID_HOTPLUG_INT_EN | SDVOC_HOTPLUG_INT_EN |
+			SDVOB_HOTPLUG_INT_EN | CRT_HOTPLUG_INT_EN);
+
+	/* Note HDMI and DP share bits */
+	if (dev_priv->hotplug_supported_mask & HDMIB_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMIB_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & HDMIC_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMIC_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & HDMID_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMID_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
+		hotplug_en |= SDVOC_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
+		hotplug_en |= SDVOB_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
+		hotplug_en |= CRT_HOTPLUG_INT_EN;
+		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
+	}
+	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+}
+
 static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
@@ -2020,7 +2046,6 @@ static int valleyview_irq_postinstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	u32 enable_mask;
-	u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
 	u32 pipestat_enable = PLANE_FLIP_DONE_INT_EN_VLV;
 	u32 render_irqs;
 	u16 msid;
@@ -2075,25 +2100,9 @@ static int valleyview_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(DPINVGTT, DPINVGTT_STATUS_MASK);
 	I915_WRITE(DPINVGTT, DPINVGTT_EN_MASK);
 #endif
-
 	I915_WRITE(VLV_MASTER_IER, MASTER_INTERRUPT_ENABLE);
-	/* Note HDMI and DP share bits */
-	if (dev_priv->hotplug_supported_mask & HDMIB_HOTPLUG_INT_STATUS)
-		hotplug_en |= HDMIB_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & HDMIC_HOTPLUG_INT_STATUS)
-		hotplug_en |= HDMIC_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & HDMID_HOTPLUG_INT_STATUS)
-		hotplug_en |= HDMID_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
-		hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
-		hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-		hotplug_en |= CRT_HOTPLUG_INT_EN;
-		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-	}
 
-	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+	valleyview_enable_hotplug_irq(dev);
 
 	return 0;
 }
@@ -2298,6 +2307,34 @@ static void i915_irq_preinstall(struct drm_device * dev)
 	POSTING_READ(IER);
 }
 
+static void i915_enable_hotplug_irq(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
+	hotplug_en &= ~(HDMIB_HOTPLUG_INT_EN | HDMIC_HOTPLUG_INT_EN |
+			HDMID_HOTPLUG_INT_EN | SDVOC_HOTPLUG_INT_EN |
+			SDVOB_HOTPLUG_INT_EN | CRT_HOTPLUG_INT_EN);
+
+	if (dev_priv->hotplug_supported_mask & HDMIB_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMIB_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & HDMIC_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMIC_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & HDMID_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMID_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
+		hotplug_en |= SDVOC_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
+		hotplug_en |= SDVOB_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
+		hotplug_en |= CRT_HOTPLUG_INT_EN;
+		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
+	}
+
+	/* Ignore TV since it's buggy */
+
+	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+}
+
 static int i915_irq_postinstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -2335,28 +2372,8 @@ static int i915_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(IER, enable_mask);
 	POSTING_READ(IER);
 
-	if (I915_HAS_HOTPLUG(dev)) {
-		u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
-
-		if (dev_priv->hotplug_supported_mask & HDMIB_HOTPLUG_INT_STATUS)
-			hotplug_en |= HDMIB_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & HDMIC_HOTPLUG_INT_STATUS)
-			hotplug_en |= HDMIC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & HDMID_HOTPLUG_INT_STATUS)
-			hotplug_en |= HDMID_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-			hotplug_en |= CRT_HOTPLUG_INT_EN;
-			hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-		}
-
-		/* Ignore TV since it's buggy */
-
-		I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
-	}
+	if (I915_HAS_HOTPLUG(dev))
+		i915_enable_hotplug_irq(dev);
 
 	intel_opregion_enable_asle(dev);
 
@@ -2519,10 +2536,54 @@ static void i965_irq_preinstall(struct drm_device * dev)
 	POSTING_READ(IER);
 }
 
-static int i965_irq_postinstall(struct drm_device *dev)
+static void i965_enable_hotplug_irq(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	u32 hotplug_en;
+
+	hotplug_en = I915_READ(PORT_HOTPLUG_EN);
+	hotplug_en &= ~(HDMIB_HOTPLUG_INT_EN | HDMIC_HOTPLUG_INT_EN |
+		HDMID_HOTPLUG_INT_EN | SDVOC_HOTPLUG_INT_EN |
+			SDVOB_HOTPLUG_INT_EN | CRT_HOTPLUG_INT_EN);
+
+	/* Note HDMI and DP share hotplug bits */
+	if (dev_priv->hotplug_supported_mask & HDMIB_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMIB_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & HDMIC_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMIC_HOTPLUG_INT_EN;
+	if (dev_priv->hotplug_supported_mask & HDMID_HOTPLUG_INT_STATUS)
+		hotplug_en |= HDMID_HOTPLUG_INT_EN;
+	if (IS_G4X(dev)) {
+		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_G4X)
+			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
+		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_G4X)
+			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
+	} else {
+		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I965)
+			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
+		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I965)
+			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
+	}
+	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
+		hotplug_en |= CRT_HOTPLUG_INT_EN;
+
+		/* Programming the CRT detection parameters tends
+		   to generate a spurious hotplug event about three
+		   seconds later.  So just do it once.
+		   */
+		if (IS_G4X(dev))
+			hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
+		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
+	}
+
+	/* Ignore TV since it's buggy */
+
+	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+}
+
+static int i965_irq_postinstall(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	u32 enable_mask;
 	u32 error_mask;
 
@@ -2563,40 +2624,7 @@ static int i965_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(IER, enable_mask);
 	POSTING_READ(IER);
 
-	/* Note HDMI and DP share hotplug bits */
-	hotplug_en = 0;
-	if (dev_priv->hotplug_supported_mask & HDMIB_HOTPLUG_INT_STATUS)
-		hotplug_en |= HDMIB_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & HDMIC_HOTPLUG_INT_STATUS)
-		hotplug_en |= HDMIC_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & HDMID_HOTPLUG_INT_STATUS)
-		hotplug_en |= HDMID_HOTPLUG_INT_EN;
-	if (IS_G4X(dev)) {
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_G4X)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_G4X)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	} else {
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I965)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I965)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	}
-	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-		hotplug_en |= CRT_HOTPLUG_INT_EN;
-
-		/* Programming the CRT detection parameters tends
-		   to generate a spurious hotplug event about three
-		   seconds later.  So just do it once.
-		   */
-		if (IS_G4X(dev))
-			hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
-		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-	}
-
-	/* Ignore TV since it's buggy */
-
-	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+	i965_enable_hotplug_irq(dev);
 
 	intel_opregion_enable_asle(dev);
 
-- 
1.7.7

[PATCH 6/8] drm/i915: Only enable hotplug irq when needed on Ironlake and later chips.

[Egbert Eich]

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   89 ++++++++++++++++++++------------------
 1 files changed, 47 insertions(+), 42 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 356472f..2da788f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1910,19 +1910,56 @@ static void valleyview_irq_preinstall(struct drm_device *dev)
  * This register is the same on all known PCH chips.
  */
 
-static void ironlake_enable_pch_hotplug(struct drm_device *dev)
+static void ironlake_enable_pch_hotplug(struct drm_device *dev, bool is_cpt)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	u32	hotplug;
 
 	hotplug = I915_READ(PCH_PORT_HOTPLUG);
-	hotplug &= ~(PORTD_PULSE_DURATION_MASK|PORTC_PULSE_DURATION_MASK|PORTB_PULSE_DURATION_MASK);
-	hotplug |= PORTD_HOTPLUG_ENABLE | PORTD_PULSE_DURATION_2ms;
-	hotplug |= PORTC_HOTPLUG_ENABLE | PORTC_PULSE_DURATION_2ms;
-	hotplug |= PORTB_HOTPLUG_ENABLE | PORTB_PULSE_DURATION_2ms;
+	hotplug &= ~(PORTD_HOTPLUG_ENABLE|PORTC_HOTPLUG_ENABLE|PORTB_HOTPLUG_ENABLE|
+		PORTD_PULSE_DURATION_MASK|PORTC_PULSE_DURATION_MASK|PORTB_PULSE_DURATION_MASK);
+	if (dev_priv->hotplug_supported_mask & (is_cpt ? SDE_PORTD_HOTPLUG_CPT : SDE_PORTD_HOTPLUG))
+		hotplug |= PORTD_HOTPLUG_ENABLE | PORTD_PULSE_DURATION_2ms;
+	if (dev_priv->hotplug_supported_mask & (is_cpt ? SDE_PORTC_HOTPLUG_CPT : SDE_PORTC_HOTPLUG))
+		hotplug |= PORTC_HOTPLUG_ENABLE | PORTC_PULSE_DURATION_2ms;
+	if (dev_priv->hotplug_supported_mask & (is_cpt ? SDE_PORTB_HOTPLUG_CPT : SDE_PORTB_HOTPLUG))
+		hotplug |= PORTB_HOTPLUG_ENABLE | PORTB_PULSE_DURATION_2ms;
 	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
 }
 
+static void cpt_enable_hotplug_irq(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	u32 pch_irq_mask;
+
+	pch_irq_mask = ~dev_priv->hotplug_supported_mask;
+
+	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
+	I915_WRITE(SDEIMR, pch_irq_mask);
+	I915_WRITE(SDEIER, dev_priv->hotplug_supported_mask);
+	POSTING_READ(SDEIER);
+
+	ironlake_enable_pch_hotplug(dev, 1);
+}
+
+static void ibx_enable_hotplug_irq(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	u32 hotplug_mask;
+	u32 pch_irq_mask;
+
+	hotplug_mask = (dev_priv->hotplug_supported_mask | SDE_AUX_MASK);
+
+	pch_irq_mask = ~hotplug_mask;
+
+	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
+	I915_WRITE(SDEIMR, pch_irq_mask);
+	I915_WRITE(SDEIER, hotplug_mask);
+	POSTING_READ(SDEIER);
+
+	ironlake_enable_pch_hotplug(dev, 0);
+}
+
 static int ironlake_irq_postinstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -1930,8 +1967,6 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
 	u32 display_mask = DE_MASTER_IRQ_CONTROL | DE_GSE | DE_PCH_EVENT |
 			   DE_PLANEA_FLIP_DONE | DE_PLANEB_FLIP_DONE;
 	u32 render_irqs;
-	u32 hotplug_mask;
-	u32 pch_irq_mask;
 
 	dev_priv->irq_mask = ~display_mask;
 
@@ -1959,27 +1994,10 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(GTIER, render_irqs);
 	POSTING_READ(GTIER);
 
-	if (HAS_PCH_CPT(dev)) {
-		hotplug_mask = (SDE_CRT_HOTPLUG_CPT |
-				SDE_PORTB_HOTPLUG_CPT |
-				SDE_PORTC_HOTPLUG_CPT |
-				SDE_PORTD_HOTPLUG_CPT);
-	} else {
-		hotplug_mask = (SDE_CRT_HOTPLUG |
-				SDE_PORTB_HOTPLUG |
-				SDE_PORTC_HOTPLUG |
-				SDE_PORTD_HOTPLUG |
-				SDE_AUX_MASK);
-	}
-
-	pch_irq_mask = ~hotplug_mask;
-
-	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
-	I915_WRITE(SDEIMR, pch_irq_mask);
-	I915_WRITE(SDEIER, hotplug_mask);
-	POSTING_READ(SDEIER);
-
-	ironlake_enable_pch_hotplug(dev);
+	if (HAS_PCH_CPT(dev))
+		cpt_enable_hotplug_irq(dev);
+	else
+		ibx_enable_hotplug_irq(dev);
 
 	if (IS_IRONLAKE_M(dev)) {
 		/* Clear & enable PCU event interrupts */
@@ -2001,8 +2019,6 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
 		DE_PLANEB_FLIP_DONE_IVB |
 		DE_PLANEA_FLIP_DONE_IVB;
 	u32 render_irqs;
-	u32 hotplug_mask;
-	u32 pch_irq_mask;
 
 	dev_priv->irq_mask = ~display_mask;
 
@@ -2026,18 +2042,7 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(GTIER, render_irqs);
 	POSTING_READ(GTIER);
 
-	hotplug_mask = (SDE_CRT_HOTPLUG_CPT |
-			SDE_PORTB_HOTPLUG_CPT |
-			SDE_PORTC_HOTPLUG_CPT |
-			SDE_PORTD_HOTPLUG_CPT);
-	pch_irq_mask = ~hotplug_mask;
-
-	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
-	I915_WRITE(SDEIMR, pch_irq_mask);
-	I915_WRITE(SDEIER, hotplug_mask);
-	POSTING_READ(SDEIER);
-
-	ironlake_enable_pch_hotplug(dev);
+	cpt_enable_hotplug_irq(dev);
 
 	return 0;
 }
-- 
1.7.7

[PATCH 7/8] drm/i915: When detecting a hotplug IRQ storm disable respective IRQs.

[Egbert Eich]

This patch disables hotplug interrupts if an 'interrupt storm'
has been detected.
Noise on the interrupt line renders the hotplug interrupt useless:
each hotplug event causes the devices to be rescanned which will
will only increase the system load.
Thus disable the hotplug interrupts and fall back to periodic
device polling.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   25 +++++++++++++++++++------
 1 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2da788f..aa4986d 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -313,12 +313,13 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	drm_helper_hpd_irq_event(dev);
 }
 
-static inline void hotplug_irq_storm_detect(struct drm_device *dev, u32 hotplug_trigger)
+static inline int hotplug_irq_storm_detect(struct drm_device *dev, u32 hotplug_trigger)
 {
 	struct drm_mode_config *mode_config = &dev->mode_config;
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_connector *connector;
 	unsigned long irqflags;
+	int ret = 0;
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 
@@ -335,12 +336,15 @@ static inline void hotplug_irq_storm_detect(struct drm_device *dev, u32 hotplug_
 				intel_connector->hpd_mark_disabled = 1;
 				pr_warn("HPD interrupt storm on connector %s disabling\n",
 					 drm_get_connector_name(connector));
+				ret = 1;
 			} else
 				intel_connector->hpd_cnt++;
 		}
 	}
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+	return ret;
 }
 
 /* defined intel_pm.c */
@@ -652,7 +656,8 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger);
+				if (hotplug_irq_storm_detect(dev, hotplug_trigger))
+					valleyview_enable_hotplug_irq(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
@@ -675,6 +680,8 @@ out:
 	return ret;
 }
 
+static void ibx_enable_hotplug_irq(struct drm_device *dev);
+
 static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -682,7 +689,8 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 	u32 hotplug_trigger = pch_iir & dev_priv->hotplug_supported_mask;
 
 	if (hotplug_trigger) {
-		hotplug_irq_storm_detect(dev, hotplug_trigger);
+		if (hotplug_irq_storm_detect(dev, hotplug_trigger))
+			ibx_enable_hotplug_irq(dev);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
 	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
@@ -720,6 +728,8 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 		DRM_DEBUG_DRIVER("PCH transcoder A underrun interrupt\n");
 }
 
+static void cpt_enable_hotplug_irq(struct drm_device *dev);
+
 static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -727,7 +737,8 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 	u32 hotplug_trigger = pch_iir & dev_priv->hotplug_supported_mask;
 
 	if (hotplug_trigger) {
-		hotplug_irq_storm_detect(dev, hotplug_trigger);
+		if (hotplug_irq_storm_detect(dev, hotplug_trigger))
+			cpt_enable_hotplug_irq(dev);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
 	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
@@ -2443,7 +2454,8 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger);
+				if (hotplug_irq_storm_detect(dev, hotplug_trigger))
+					i915_enable_hotplug_irq(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
@@ -2694,7 +2706,8 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger);
+				if (hotplug_irq_storm_detect(dev, hotplug_trigger))
+					i965_enable_hotplug_irq(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
-- 
1.7.7

[PATCH 8/8] drm/i915: Add Reenable Timer to turn Hotplug Detection back on.

[Egbert Eich]

We disable hoptplug detection when we encounter a hotplug event
storm. Still hotplug detection is required on some outputs (like
Display Port). The interrupt storm may be only temporary (on certain
Dell Laptops for instance it happens at certain charging states of
the system). Thus we enable it after a certain grace period (2 minutes).
Should the interrupt storm persist it will be detected immediately
and it will be disabled again.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h  |    2 +
 drivers/gpu/drm/i915/i915_irq.c  |   58 ++++++++++++++++++++++++++++++++++++--
 drivers/gpu/drm/i915/intel_drv.h |    6 +++-
 3 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d7ad677..e3c3121 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -668,6 +668,8 @@ typedef struct drm_i915_private {
 
 	u32 hotplug_supported_mask;
 	struct work_struct hotplug_work;
+#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
+	struct timer_list hotplug_reenable_timer;
 
 	int num_pipe;
 	int num_pch_pll;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index aa4986d..637f68d 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -279,6 +279,8 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
+static void i915_reenable_hotplug_timer_func(unsigned long data);
+
 static void i915_hotplug_work_func(struct work_struct *work)
 {
 	drm_i915_private_t *dev_priv = container_of(work, drm_i915_private_t,
@@ -288,6 +290,7 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_connector *connector;
 	struct intel_encoder *encoder;
 	unsigned long irqflags;
+	bool reset_timer = false;
 
 	mutex_lock(&mode_config->mutex);
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
@@ -295,12 +298,17 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
 		struct intel_connector *intel_connector = to_intel_connector(connector);
-		if (intel_connector->hpd_mark_disabled) {
-			intel_connector->hpd_mark_disabled = 0;
+		if (intel_connector->hpd_mark_disabled == HPD_MARKED_DISABLED) {
+			intel_connector->hpd_mark_disabled = HPD_DISABLED;
 			connector->polled = DRM_CONNECTOR_POLL_CONNECT
 				 | DRM_CONNECTOR_POLL_DISCONNECT;
+			reset_timer = true;
 		}
 	}
+	if (reset_timer)
+		mod_timer(&dev_priv->hotplug_reenable_timer,
+			  jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
+
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
 	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
@@ -333,7 +341,7 @@ static inline int hotplug_irq_storm_detect(struct drm_device *dev, u32 hotplug_t
 				intel_connector->hpd_cnt = 0;
 			} else if (intel_connector->hpd_cnt > 5) {
 				dev_priv->hotplug_supported_mask &= ~intel_connector->hpd_status_bit;
-				intel_connector->hpd_mark_disabled = 1;
+				intel_connector->hpd_mark_disabled = HPD_MARKED_DISABLED;
 				pr_warn("HPD interrupt storm on connector %s disabling\n",
 					 drm_get_connector_name(connector));
 				ret = 1;
@@ -2143,6 +2151,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
 	I915_WRITE(VLV_IMR, 0xffffffff);
 	I915_WRITE(VLV_IER, 0x0);
 	POSTING_READ(VLV_IER);
+
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
 }
 
 static void ironlake_irq_uninstall(struct drm_device *dev)
@@ -2165,6 +2175,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
 	I915_WRITE(SDEIMR, 0xffffffff);
 	I915_WRITE(SDEIER, 0x0);
 	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
+
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
 }
 
 static void i8xx_irq_preinstall(struct drm_device * dev)
@@ -2533,6 +2545,8 @@ static void i915_irq_uninstall(struct drm_device * dev)
 	I915_WRITE(IER, 0x0);
 
 	I915_WRITE(IIR, I915_READ(IIR));
+
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
 }
 
 static void i965_irq_preinstall(struct drm_device * dev)
@@ -2788,6 +2802,42 @@ static void i965_irq_uninstall(struct drm_device * dev)
 		I915_WRITE(PIPESTAT(pipe),
 			   I915_READ(PIPESTAT(pipe)) & 0x8000ffff);
 	I915_WRITE(IIR, I915_READ(IIR));
+
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+}
+
+static void i915_reenable_hotplug_timer_func(unsigned long data)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *)data;
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct drm_connector *connector;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		struct intel_connector *intel_connector = to_intel_connector(connector);
+		if (intel_connector->hpd_mark_disabled == HPD_DISABLED) {
+			intel_connector->hpd_mark_disabled = HPD_ENABLED;
+			dev_priv->hotplug_supported_mask |= intel_connector->hpd_status_bit;
+			DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
+					 drm_get_connector_name(connector));
+			connector->polled = DRM_CONNECTOR_POLL_HPD;
+			if (IS_HASWELL(dev) ||
+			    IS_IVYBRIDGE(dev) ||
+			    (HAS_PCH_SPLIT(dev) && HAS_PCH_CPT(dev)))
+				cpt_enable_hotplug_irq(dev);
+			else if (HAS_PCH_SPLIT(dev))  /* ! HAS_PCH_CPT(dev) */
+				ibx_enable_hotplug_irq(dev);
+			else if (IS_VALLEYVIEW(dev))
+				valleyview_enable_hotplug_irq(dev);
+			else if (INTEL_INFO(dev)->gen == 3)
+				i915_enable_hotplug_irq(dev);
+			else
+				i965_enable_hotplug_irq(dev);
+		}
+	}
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 }
 
 void intel_irq_init(struct drm_device *dev)
@@ -2798,6 +2848,8 @@ void intel_irq_init(struct drm_device *dev)
 	INIT_WORK(&dev_priv->error_work, i915_error_work_func);
 	INIT_WORK(&dev_priv->rps.work, gen6_pm_rps_work);
 	INIT_WORK(&dev_priv->l3_parity.error_work, ivybridge_parity_work);
+	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
+		    (unsigned long) dev_priv);
 
 	dev->driver->get_vblank_counter = i915_get_vblank_counter;
 	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 2d003d9..1ca5295 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -197,7 +197,11 @@ struct intel_connector {
 	/* bookkeeping for irq storm detection */
 	int hpd_cnt;
 	unsigned long last_hpd_jiffies;
-	bool hpd_mark_disabled;
+	enum {
+		HPD_ENABLED = 0,
+		HPD_MARKED_DISABLED,
+		HPD_DISABLED,
+	} hpd_mark_disabled;
 };
 
 struct intel_crtc {
-- 
1.7.7

Re: [PATCH 1/8] drm/i915: Remove pch_rq_mask from struct drm_i915_private.

[Daniel Vetter]

On Thu, Jan 10, 2013 at 10:02:39AM -0500, Egbert Eich wrote:
> This variable is only used locally in the irq postinstall
> functions for ivybridge and ironlake.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>

Applied to dinq with a minor conflict resolved, thanks for the patch.
-Daniel
> ---
>  drivers/gpu/drm/i915/i915_drv.h |    1 -
>  drivers/gpu/drm/i915/i915_irq.c |   10 ++++++----
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index ed30595..eeaf2a8 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -665,7 +665,6 @@ typedef struct drm_i915_private {
>  	u32 pipestat[2];
>  	u32 irq_mask;
>  	u32 gt_irq_mask;
> -	u32 pch_irq_mask;
>  
>  	u32 hotplug_supported_mask;
>  	struct work_struct hotplug_work;
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 2220dec..bb5e6d8 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1857,6 +1857,7 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
>  			   DE_PLANEA_FLIP_DONE | DE_PLANEB_FLIP_DONE;
>  	u32 render_irqs;
>  	u32 hotplug_mask;
> +	u32 pch_irq_mask;
>  
>  	dev_priv->irq_mask = ~display_mask;
>  
> @@ -1897,10 +1898,10 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
>  				SDE_AUX_MASK);
>  	}
>  
> -	dev_priv->pch_irq_mask = ~hotplug_mask;
> +	pch_irq_mask = ~hotplug_mask;
>  
>  	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
> -	I915_WRITE(SDEIMR, dev_priv->pch_irq_mask);
> +	I915_WRITE(SDEIMR, pch_irq_mask);
>  	I915_WRITE(SDEIER, hotplug_mask);
>  	POSTING_READ(SDEIER);
>  
> @@ -1927,6 +1928,7 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
>  		DE_PLANEA_FLIP_DONE_IVB;
>  	u32 render_irqs;
>  	u32 hotplug_mask;
> +	u32 pch_irq_mask;
>  
>  	dev_priv->irq_mask = ~display_mask;
>  
> @@ -1954,10 +1956,10 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
>  			SDE_PORTB_HOTPLUG_CPT |
>  			SDE_PORTC_HOTPLUG_CPT |
>  			SDE_PORTD_HOTPLUG_CPT);
> -	dev_priv->pch_irq_mask = ~hotplug_mask;
> +	pch_irq_mask = ~hotplug_mask;
>  
>  	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
> -	I915_WRITE(SDEIMR, dev_priv->pch_irq_mask);
> +	I915_WRITE(SDEIMR, pch_irq_mask);
>  	I915_WRITE(SDEIER, hotplug_mask);
>  	POSTING_READ(SDEIER);
>  
> -- 
> 1.7.7
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Daniel Vetter]

On Thu, Jan 10, 2013 at 10:02:38AM -0500, Egbert Eich wrote:
> Despite the many attempts to fix the issue with noisy hotplug interrupt lines
> we are still seeing systems that suffer from this:
> Recently we encountered a rather large scale installation of Q35 systems
> which was hit by this issue rather severely: It seemed as if not all machines
> of the same model were hit equally bad, in the worst cased hotplug
> interrupt noise caused several 1000 interrupts / s. Those machines would not
> even boot, instead the interrupt handler and the scheduled workers would keep
> the CPU  busy that eventually the watchdog would kick in and issue an NMI.
> Other machines only received severa 10s to 100s of interrupts per sec - those
> machines would run properly - just with an excessive system load.
> More thorough investigations seemed to indicate that this condition
> only happen at certain video modes.
> 
> On another system - a laptop - a hotplug interrupt 'storm' occurred when 
> it was charging and the batteries were at certain charge levels. While 
> the system was still running fine its load was high enough that the user
> noticed from the fan noise that a problem existed.
> The latter system had a Sandybridge chipset, thus a totally different 
> generation from the former.
> 
> All those cases seemed to have been caused by cross talk on badly routed 
> hotplug signal lines (or voltage instabilities).
> This led to the conclusion that instead of trying to work around these
> 'storms' for each individual system, there should be a generic way to detect 
> such a condition and take appropriate action:
> 
> This patch series implements a hotplug 'storm' detection, disables the
> respective interrupt for the hotplug pin when this condition is detected
> and reverts to periodic output polling on the affected connector.
> After a grace period of 2 minutes it will reenable hotplug on the affected
> line. This will take care of cases in which this condition is only temporary.
> Should the 'storm' condtion persist, this cycle will start over again.
> 
> To implement this some rearrangements in the code were required:
> - The interrupt status bit which signals a hotplug needed to be recorded
>   for each connector.
> - The interrupt enable functions needed to be separate, also they need 
>   to be able to enable interrupts for each hotplug line independently.

Nice work, and we know that we need this since quite a while. But
unfortunately we've not yet come around to implement something. Some
high-level comments on how I think this should best be handled:

- imo dv_priv->hotplug_supported_mask should die - it leaks platform
  specific irq magic from i915_irq.c into every connector/encoder. And we
  have had the bugs and confusions to prove that it's not a good idea. I
  think it'd be better if we add a new HOTPLUG_PIN_FOO enum that encoders
  register interest in, and the platform code in i915_irq.c then maps
  from/to that. On a quick check we have hotplug pins for CRT, TV,
  SDVO_B&C and PORT_A-D (for DP&HDMI).

  Also note that on PCH_SPLIT platforms port A is not in the same
  register, further platforms will make an even cuter mess of this ...

- I think the the hpd pin should be track in the encoder, not in the
  connector. The only encoders where there's not a 1:1 relationship (sdvo
  and ddi on hsw) want it there. Also, we already have the ->hot_plug
  callback in the encoder, which will be useful for later extensions.

- Since some encoders share the same hpd pin (HDMI&DP on pre-hsw) I think
  we should keep the noise statistic data in the device's dev_priv
  somewhere in an array, with one set for each hpd pin from the enum above.

- In 3.8 the drm hpd/polling helpers are much improved and don't randomly
  poll everything any more. So if a hpd connector isn't marked as
  OUTPUT_POLL, it wont ever get polled. Which means if you disable the hpd
  irq for it, we need to have our own poll work to do that for us. The
  long-term goal I have is to pimp the encoder->hot_plug callback also for
  this case, to avoid re-running the connector detect code on unrelated
  outputs (which can sometimes cause havoc).

  Eventually a want a hpd interrupt to only run the ->hot_plug callbacks
  on encoders which are interested in that signal, hence this slight
  overkill ... Ofc, that requires that we move a lot of the ->detect logic
  into ->hot_plug, but that's the only way to do sane EDID cache and
  similar things on outputs where hpd should work (DP/HDMI).

- The math buff in me would like hpd stroms to gracefully degrade into
  polling at 10s or so. We could achieve that with irq source masking and
  scheduling the work item to do the hotplug handling with an (increasing)
  delay if there's too many interrupts from a given hpd pin. But that
  requires that we can mask hotplug interrupts properly, which seems to be
  impossible with the PORT_HOTPLUG regs on gmch/SoC platforms :( So I
  think your logic is nice enough ;-)

Yours, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Egbert Eich]

Hi Daniel,

On Fri, Jan 11, 2013 at 09:34:08PM +0100, Daniel Vetter wrote:
> 
> Nice work, and we know that we need this since quite a while. But
> unfortunately we've not yet come around to implement something. Some
> high-level comments on how I think this should best be handled:
> 
> - imo dv_priv->hotplug_supported_mask should die - it leaks platform
>   specific irq magic from i915_irq.c into every connector/encoder. And we
>   have had the bugs and confusions to prove that it's not a good idea. I
>   think it'd be better if we add a new HOTPLUG_PIN_FOO enum that encoders
>   register interest in, and the platform code in i915_irq.c then maps
>   from/to that. On a quick check we have hotplug pins for CRT, TV,
>   SDVO_B&C and PORT_A-D (for DP&HDMI).

I thought along the same lines, I just didn't want to go quite as far.
Therefore I added functions in i915_irq.c to set these depending on the
connector.

> 
>   Also note that on PCH_SPLIT platforms port A is not in the same
>   register, further platforms will make an even cuter mess of this ...

Ok, I will look into that.

> 
> - I think the the hpd pin should be track in the encoder, not in the
>   connector. The only encoders where there's not a 1:1 relationship (sdvo
>   and ddi on hsw) want it there. Also, we already have the ->hot_plug
>   callback in the encoder, which will be useful for later extensions.
> 
> - Since some encoders share the same hpd pin (HDMI&DP on pre-hsw) I think
>   we should keep the noise statistic data in the device's dev_priv
>   somewhere in an array, with one set for each hpd pin from the enum above.

This would also be an option. I did notice that these pins are shared, it
didn't cause any issues as always both connectors got flagged simultaniously.
On the other hand calling the same disable/enable twice when traversing the
connector list is sorta ugly.

> 
> - In 3.8 the drm hpd/polling helpers are much improved and don't randomly
>   poll everything any more. So if a hpd connector isn't marked as
>   OUTPUT_POLL, it wont ever get polled. Which means if you disable the hpd
>   irq for it, we need to have our own poll work to do that for us. The
>   long-term goal I have is to pimp the encoder->hot_plug callback also for
>   this case, to avoid re-running the connector detect code on unrelated
>   outputs (which can sometimes cause havoc).

I do change the state of the 'polled' member when I disable/reenable hotplug
interrupts already. This part therefore should work fine already.

> 
>   Eventually a want a hpd interrupt to only run the ->hot_plug callbacks
>   on encoders which are interested in that signal, hence this slight
>   overkill ... Ofc, that requires that we move a lot of the ->detect logic

This was exactly my question: we have all information at hand now to do this
and I can easily add this. The downside is that if the information about
the mapping is not accurate (ie if a vendor routes HPD lines differently)
this connector will never light up :(
As it is now since we poll everything when an interrupt happened we can
be sure that we catch all connectors even if the mapping in our tables
don't reflect what's wired on the board.
I didn't just go ahead and implement this yet as I've gotten too pessimistic.

>   into ->hot_plug, but that's the only way to do sane EDID cache and
>   similar things on outputs where hpd should work (DP/HDMI).

... But since you suggest this I will gladly add this :)

> 
> - The math buff in me would like hpd stroms to gracefully degrade into
>   polling at 10s or so. We could achieve that with irq source masking and
>   scheduling the work item to do the hotplug handling with an (increasing)
>   delay if there's too many interrupts from a given hpd pin. But that
>   requires that we can mask hotplug interrupts properly, which seems to be
>   impossible with the PORT_HOTPLUG regs on gmch/SoC platforms :( So I
>   think your logic is nice enough ;-)

What you suggest would be possible with some small changes to my code I
guess. I just fear if we do have an IRQ storm 10s would be too short - on
a completely idle system this might be the prime source of wakeups.

I believe I can spare some hours to think about and work in your 
suggestions.

Cheers,
	Egbert.

Re: [PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Daniel Vetter]

On Thu, Jan 17, 2013 at 03:01:06PM +0100, Egbert Eich wrote:
> Hi Daniel,
> 
> On Fri, Jan 11, 2013 at 09:34:08PM +0100, Daniel Vetter wrote:
> > 
> > Nice work, and we know that we need this since quite a while. But
> > unfortunately we've not yet come around to implement something. Some
> > high-level comments on how I think this should best be handled:
> > 
> > - imo dv_priv->hotplug_supported_mask should die - it leaks platform
> >   specific irq magic from i915_irq.c into every connector/encoder. And we
> >   have had the bugs and confusions to prove that it's not a good idea. I
> >   think it'd be better if we add a new HOTPLUG_PIN_FOO enum that encoders
> >   register interest in, and the platform code in i915_irq.c then maps
> >   from/to that. On a quick check we have hotplug pins for CRT, TV,
> >   SDVO_B&C and PORT_A-D (for DP&HDMI).
> 
> I thought along the same lines, I just didn't want to go quite as far.
> Therefore I added functions in i915_irq.c to set these depending on the
> connector.
> 
> > 
> >   Also note that on PCH_SPLIT platforms port A is not in the same
> >   register, further platforms will make an even cuter mess of this ...
> 
> Ok, I will look into that.
> 
> > 
> > - I think the the hpd pin should be track in the encoder, not in the
> >   connector. The only encoders where there's not a 1:1 relationship (sdvo
> >   and ddi on hsw) want it there. Also, we already have the ->hot_plug
> >   callback in the encoder, which will be useful for later extensions.
> > 
> > - Since some encoders share the same hpd pin (HDMI&DP on pre-hsw) I think
> >   we should keep the noise statistic data in the device's dev_priv
> >   somewhere in an array, with one set for each hpd pin from the enum above.
> 
> This would also be an option. I did notice that these pins are shared, it
> didn't cause any issues as always both connectors got flagged simultaniously.
> On the other hand calling the same disable/enable twice when traversing the
> connector list is sorta ugly.

Yeah, I mostly want to have a clear 1:1 relationship between interrupt
lines and the statistics about the noise on them ...

> > - In 3.8 the drm hpd/polling helpers are much improved and don't randomly
> >   poll everything any more. So if a hpd connector isn't marked as
> >   OUTPUT_POLL, it wont ever get polled. Which means if you disable the hpd
> >   irq for it, we need to have our own poll work to do that for us. The
> >   long-term goal I have is to pimp the encoder->hot_plug callback also for
> >   this case, to avoid re-running the connector detect code on unrelated
> >   outputs (which can sometimes cause havoc).
> 
> I do change the state of the 'polled' member when I disable/reenable hotplug
> interrupts already. This part therefore should work fine already.

Hm, I've missed that, despite looking for it in the patches. One thing to
note is that the poll work will disable itself if there's no connector
with one of the POLL flags set in 3.8, so I think you need to kick it
again when polling. Another thing to keep in mind is that we have encoders
with POLL and HDP connectors (sometimes on the same one) - SDVO is the
prime example since polling seems to work, but not too reliably. Hence we
need the polling as a backup. To correctly restore those flags I guess we
need a saved_polled variable in intel_connector which we need to restore
when enabling the the hpd line again.

> >   Eventually a want a hpd interrupt to only run the ->hot_plug callbacks
> >   on encoders which are interested in that signal, hence this slight
> >   overkill ... Ofc, that requires that we move a lot of the ->detect logic
> 
> This was exactly my question: we have all information at hand now to do this
> and I can easily add this. The downside is that if the information about
> the mapping is not accurate (ie if a vendor routes HPD lines differently)
> this connector will never light up :(
> As it is now since we poll everything when an interrupt happened we can
> be sure that we catch all connectors even if the mapping in our tables
> don't reflect what's wired on the board.
> I didn't just go ahead and implement this yet as I've gotten too pessimistic.

I share your pessimism, and we certainly need tons of special cases to
make this work. E.g. the sdvo case, but also DP->VGA dongles where the
forwarded hotplug events are as unreliable as plain VGA. And that exercise
in only calling the right hpd handlers is only really useful if we cache
the EDID, since userspace will do a full scan after it receives the
hotplug event anyway. My idea is that the ->hotplug callback will then
only invalidate the edid and we still do a full scan through all
connector->detect callbacks. But for those outputs with reliably hdp we
won't touch the hw (and so also optimize away the delays when userspace
does the same afterwards). Once a hpd storm is detect and we switch to
polling, we'd need to mark that output as unreliable to disable all edid
caching.

We could even try to cache the edid for unreliable outputs like VGA for a
short time ...

> >   into ->hot_plug, but that's the only way to do sane EDID cache and
> >   similar things on outputs where hpd should work (DP/HDMI).
> 
> ... But since you suggest this I will gladly add this :)

Imo better in a follow-up series, since there's quite some prep work
involved. And I also think that it makes more sense to implement EDID
caching first (which in turn requires some code to detect hpd irq storms
...).

> > - The math buff in me would like hpd stroms to gracefully degrade into
> >   polling at 10s or so. We could achieve that with irq source masking and
> >   scheduling the work item to do the hotplug handling with an (increasing)
> >   delay if there's too many interrupts from a given hpd pin. But that
> >   requires that we can mask hotplug interrupts properly, which seems to be
> >   impossible with the PORT_HOTPLUG regs on gmch/SoC platforms :( So I
> >   think your logic is nice enough ;-)
> 
> What you suggest would be possible with some small changes to my code I
> guess. I just fear if we do have an IRQ storm 10s would be too short - on
> a completely idle system this might be the prime source of wakeups.

I've misread your code and didn't realize that you rely on the output poll
work for disabled hpd lines. I think the 2m delay in trying to re-enable
outputs is more than fair enough. If we start to do fancy things with the
DP/HDMI short pulses (i.e. reconfiguring downstream DP ports) we might
need to reconsider the tuning values a bit. But the current values look
sane to me.

> I believe I can spare some hours to think about and work in your 
> suggestions.

Awesome!

Cheers, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Egbert Eich]

Hi Daniel,

I've played around a bit now, and implemented your suggestions:

On Thu, Jan 17, 2013 at 03:45:26PM +0100, Daniel Vetter wrote:
> On Thu, Jan 17, 2013 at 03:01:06PM +0100, Egbert Eich wrote:
> > Hi Daniel,
> > 
> > On Fri, Jan 11, 2013 at 09:34:08PM +0100, Daniel Vetter wrote:
> > > 
> > > Nice work, and we know that we need this since quite a while. But
> > > unfortunately we've not yet come around to implement something. Some
> > > high-level comments on how I think this should best be handled:
> > > 
> > > - imo dv_priv->hotplug_supported_mask should die - it leaks platform
> > >   specific irq magic from i915_irq.c into every connector/encoder. And we
> > >   have had the bugs and confusions to prove that it's not a good idea. I
> > >   think it'd be better if we add a new HOTPLUG_PIN_FOO enum that encoders
> > >   register interest in, and the platform code in i915_irq.c then maps
> > >   from/to that. On a quick check we have hotplug pins for CRT, TV,
> > >   SDVO_B&C and PORT_A-D (for DP&HDMI).
> > 
> > I thought along the same lines, I just didn't want to go quite as far.
> > Therefore I added functions in i915_irq.c to set these depending on the
> > connector.
> > 
> > > 
> > >   Also note that on PCH_SPLIT platforms port A is not in the same
> > >   register, further platforms will make an even cuter mess of this ...
> > 
> > Ok, I will look into that.
> > 

So far I have not seen anywhere where there's hotplug support for PORT_A.
PORT_A is marked as an internal connector without any HPD.

> > > 
> > > - I think the the hpd pin should be track in the encoder, not in the
> > >   connector. The only encoders where there's not a 1:1 relationship (sdvo
> > >   and ddi on hsw) want it there. Also, we already have the ->hot_plug
> > >   callback in the encoder, which will be useful for later extensions.

For SDVO it is definitely much simpler to track this in the encoder.
However in the IRQ handling code we always need to take the detour thru
the connector as the drm code expects any hotplog related information in
the connector.
To get the connector we always have to walk thru the connector list and
obtain the associated encoder. Walking thru the encoder list isn't 
sufficient as there is no easy way from encoder to connector.
I don't have a strong preference either way - in the code I'm currently 
playing around with I keep this information in struct intel_encoder.

> > > 
> > > - Since some encoders share the same hpd pin (HDMI&DP on pre-hsw) I think
> > >   we should keep the noise statistic data in the device's dev_priv
> > >   somewhere in an array, with one set for each hpd pin from the enum above.
> > 
> > This would also be an option. I did notice that these pins are shared, it
> > didn't cause any issues as always both connectors got flagged simultaniously.
> > On the other hand calling the same disable/enable twice when traversing the
> > connector list is sorta ugly.
> 
> Yeah, I mostly want to have a clear 1:1 relationship between interrupt
> lines and the statistics about the noise on them ...

Yup. That's easy to do. In fact in my original prove of concept implementation
I had it that way. However I was not sure if it's appreciated to add such 
bookkeeping in such a global fashion.

> 
> > > - In 3.8 the drm hpd/polling helpers are much improved and don't randomly
> > >   poll everything any more. So if a hpd connector isn't marked as
> > >   OUTPUT_POLL, it wont ever get polled. Which means if you disable the hpd
> > >   irq for it, we need to have our own poll work to do that for us. The
> > >   long-term goal I have is to pimp the encoder->hot_plug callback also for
> > >   this case, to avoid re-running the connector detect code on unrelated
> > >   outputs (which can sometimes cause havoc).
> > 
> > I do change the state of the 'polled' member when I disable/reenable hotplug
> > interrupts already. This part therefore should work fine already.
> 
> Hm, I've missed that, despite looking for it in the patches. One thing to
> note is that the poll work will disable itself if there's no connector
> with one of the POLL flags set in 3.8, so I think you need to kick it
> again when polling. Another thing to keep in mind is that we have encoders

Exactly. This is something I had missed. It's however easily fixed by
calling drm_kms_helper_poll_enable() when changing the settings.

> with POLL and HDP connectors (sometimes on the same one) - SDVO is the
> prime example since polling seems to work, but not too reliably. Hence we
> need the polling as a backup. To correctly restore those flags I guess we
> need a saved_polled variable in intel_connector which we need to restore
> when enabling the the hpd line again.

I don't see this in the code (drm-intel-testing pulled last Friday).
On any connector it is either the DRM_CONNECTOR_POLL_HPD or the 
DRM_CONNECTOR_POLL_CONNECT (mostly with the DRM_CONNECTOR_POLL_DISCONNECT flag)
set but not both.
Of course it could be done like you suggest, ie. continue polling despite
waiting for interrupts, but this begs the question if we should not resort
to polling entirely: the only benefit of doing HDP would be that we would
get informed about an output change more quickly.

> 
> > >   Eventually a want a hpd interrupt to only run the ->hot_plug callbacks
> > >   on encoders which are interested in that signal, hence this slight
> > >   overkill ... Ofc, that requires that we move a lot of the ->detect logic
> > 
> > This was exactly my question: we have all information at hand now to do this
> > and I can easily add this. The downside is that if the information about
> > the mapping is not accurate (ie if a vendor routes HPD lines differently)
> > this connector will never light up :(
> > As it is now since we poll everything when an interrupt happened we can
> > be sure that we catch all connectors even if the mapping in our tables
> > don't reflect what's wired on the board.
> > I didn't just go ahead and implement this yet as I've gotten too pessimistic.
> 
> I share your pessimism, and we certainly need tons of special cases to
> make this work. E.g. the sdvo case, but also DP->VGA dongles where the
> forwarded hotplug events are as unreliable as plain VGA. And that exercise
> in only calling the right hpd handlers is only really useful if we cache
> the EDID, since userspace will do a full scan after it receives the
> hotplug event anyway. My idea is that the ->hotplug callback will then
> only invalidate the edid and we still do a full scan through all
> connector->detect callbacks. But for those outputs with reliably hdp we
> won't touch the hw (and so also optimize away the delays when userspace
> does the same afterwards). Once a hpd storm is detect and we switch to
> polling, we'd need to mark that output as unreliable to disable all edid
> caching.
> 
> We could even try to cache the edid for unreliable outputs like VGA for a
> short time ...
> 
> > >   into ->hot_plug, but that's the only way to do sane EDID cache and
> > >   similar things on outputs where hpd should work (DP/HDMI).
> > 
> > ... But since you suggest this I will gladly add this :)
> 
> Imo better in a follow-up series, since there's quite some prep work
> involved. And I also think that it makes more sense to implement EDID
> caching first (which in turn requires some code to detect hpd irq storms
> ...).

I had sent a patch for EDID caching on the DRM level to Dave last December. 
I received some comments and suggestions from Ville from Intel which I had 
worked in - however I have not seen any reaction from Dave, yet.

Maybe you want to take a look at this. It cannot cache in all situations
where caching would be useful and possible. It still should do a fairly good
job of caching EDID extension blocks. This is because it currently 
lacks any driver interface and thus only can do as much as you can do
without a deeper knowledge of what's going on on the hardware level.

On the other hand I believe I can add selective probing quite easily.
> 
> > > - The math buff in me would like hpd stroms to gracefully degrade into
> > >   polling at 10s or so. We could achieve that with irq source masking and
> > >   scheduling the work item to do the hotplug handling with an (increasing)
> > >   delay if there's too many interrupts from a given hpd pin. But that
> > >   requires that we can mask hotplug interrupts properly, which seems to be
> > >   impossible with the PORT_HOTPLUG regs on gmch/SoC platforms :( So I
> > >   think your logic is nice enough ;-)
> > 
> > What you suggest would be possible with some small changes to my code I
> > guess. I just fear if we do have an IRQ storm 10s would be too short - on
> > a completely idle system this might be the prime source of wakeups.
> 
> I've misread your code and didn't realize that you rely on the output poll
> work for disabled hpd lines. I think the 2m delay in trying to re-enable
> outputs is more than fair enough. If we start to do fancy things with the
> DP/HDMI short pulses (i.e. reconfiguring downstream DP ports) we might
> need to reconsider the tuning values a bit. But the current values look
> sane to me.

Ok. It was an ad-hock choice trying to maintain a blanace between systems
which exhibit this behavior only under certain circumstances and others which
have it more or less permanently.

> 
> > I believe I can spare some hours to think about and work in your 
> > suggestions.
> 
> Awesome!

:)

Cheers,
	Egbert.

Re: [PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Daniel Vetter]

On Tue, Jan 22, 2013 at 2:22 PM, Egbert Eich <eich@freedesktop.org> wrote:
> On Thu, Jan 17, 2013 at 03:45:26PM +0100, Daniel Vetter wrote:
>> On Thu, Jan 17, 2013 at 03:01:06PM +0100, Egbert Eich wrote:
>> > Hi Daniel,
>> >
>> > On Fri, Jan 11, 2013 at 09:34:08PM +0100, Daniel Vetter wrote:
>> > >
>> > > Nice work, and we know that we need this since quite a while. But
>> > > unfortunately we've not yet come around to implement something. Some
>> > > high-level comments on how I think this should best be handled:
>> > >
>> > > - imo dv_priv->hotplug_supported_mask should die - it leaks platform
>> > >   specific irq magic from i915_irq.c into every connector/encoder. And we
>> > >   have had the bugs and confusions to prove that it's not a good idea. I
>> > >   think it'd be better if we add a new HOTPLUG_PIN_FOO enum that encoders
>> > >   register interest in, and the platform code in i915_irq.c then maps
>> > >   from/to that. On a quick check we have hotplug pins for CRT, TV,
>> > >   SDVO_B&C and PORT_A-D (for DP&HDMI).
>> >
>> > I thought along the same lines, I just didn't want to go quite as far.
>> > Therefore I added functions in i915_irq.c to set these depending on the
>> > connector.
>> >
>> > >
>> > >   Also note that on PCH_SPLIT platforms port A is not in the same
>> > >   register, further platforms will make an even cuter mess of this ...
>> >
>> > Ok, I will look into that.
>> >
>
> So far I have not seen anywhere where there's hotplug support for PORT_A.
> PORT_A is marked as an internal connector without any HPD.

Hm, I've thought the hw supports short dp pulses on eDP port A in case
the panel needs our attention, but maybe I've mixed that up with the
dp aux irq for port A. In any case, that's easy to add if we need it.

>
>> > >
>> > > - I think the the hpd pin should be track in the encoder, not in the
>> > >   connector. The only encoders where there's not a 1:1 relationship (sdvo
>> > >   and ddi on hsw) want it there. Also, we already have the ->hot_plug
>> > >   callback in the encoder, which will be useful for later extensions.
>
> For SDVO it is definitely much simpler to track this in the encoder.
> However in the IRQ handling code we always need to take the detour thru
> the connector as the drm code expects any hotplog related information in
> the connector.

Yeah, once we start filtering irq handling to only the ports affect,
the current code will get messy. Which is why I think we should move
the actual hpd handling into encoder->hotplug (and no longer call
every ->detect callback). But I'm not too sure about it, and it can be
done later on anyway.

> To get the connector we always have to walk thru the connector list and
> obtain the associated encoder. Walking thru the encoder list isn't
> sufficient as there is no easy way from encoder to connector.
> I don't have a strong preference either way - in the code I'm currently
> playing around with I keep this information in struct intel_encoder.

Can't we just loop over all connectors and before we update the
hotplug state check whether the attached intel encoder is interested
in the hpd irq we're processing? Or do I miss something here?

>> with POLL and HDP connectors (sometimes on the same one) - SDVO is the
>> prime example since polling seems to work, but not too reliably. Hence we
>> need the polling as a backup. To correctly restore those flags I guess we
>> need a saved_polled variable in intel_connector which we need to restore
>> when enabling the the hpd line again.
>
> I don't see this in the code (drm-intel-testing pulled last Friday).
> On any connector it is either the DRM_CONNECTOR_POLL_HPD or the
> DRM_CONNECTOR_POLL_CONNECT (mostly with the DRM_CONNECTOR_POLL_DISCONNECT flag)
> set but not both.
> Of course it could be done like you suggest, ie. continue polling despite
> waiting for interrupts, but this begs the question if we should not resort
> to polling entirely: the only benefit of doing HDP would be that we would
> get informed about an output change more quickly.

I mean that different connectors which use the same hpd line could use
both polling and non-polling modes since there's only one hpd line per
sdvo encoder. So we need to be a bit careful with which part of our
detect code handles which pieces of hw and that we don't lose anything
when switching modes.

> I had sent a patch for EDID caching on the DRM level to Dave last December.
> I received some comments and suggestions from Ville from Intel which I had
> worked in - however I have not seen any reaction from Dave, yet.

Hm, missed that, I'll take a look again.

> Maybe you want to take a look at this. It cannot cache in all situations
> where caching would be useful and possible. It still should do a fairly good
> job of caching EDID extension blocks. This is because it currently
> lacks any driver interface and thus only can do as much as you can do
> without a deeper knowledge of what's going on on the hardware level.

Atm I'm less sure about what we really should do wrt edid caching. One
ugly problem is boot-up, where a bunch of userspace pieces all want to
figure out the optimal configuration, but where it's pretty pointless
to re-query to hw all the time. So I wonder whether we shouldn't have
temporal caching of even unreliable outputs (e.g. a few seconds), with
an option for drivers to invalidate the cache on e.g. a hpd interrupt.

Another ugly issue is when people disconnect outputs slowly so that we
get the hpd interrupt _before_ the cable is fully unplugged. We've
tried to fix those by checking the relevant hpd line state, but on
noisy lines that won't really work out well (and we already have the
regression bugs to prove it's a bad idea). So imo that entire
caching/re-probing topic needs more thought.

Cheers, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH 0/8] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Egbert Eich]

On Tue, Jan 22, 2013 at 02:48:29PM +0100, Daniel Vetter wrote:
> On Tue, Jan 22, 2013 at 2:22 PM, Egbert Eich <eich@freedesktop.org> wrote:
> 
> Hm, I've thought the hw supports short dp pulses on eDP port A in case
> the panel needs our attention, but maybe I've mixed that up with the
> dp aux irq for port A. In any case, that's easy to add if we need it.

Yes, of course.
> 
> >
> >
> > For SDVO it is definitely much simpler to track this in the encoder.
> > However in the IRQ handling code we always need to take the detour thru
> > the connector as the drm code expects any hotplog related information in
> > the connector.
> 
> Yeah, once we start filtering irq handling to only the ports affect,
> the current code will get messy. Which is why I think we should move
> the actual hpd handling into encoder->hotplug (and no longer call
> every ->detect callback). But I'm not too sure about it, and it can be
> done later on anyway.

Yeah, this looks easily doable.

> 
> > To get the connector we always have to walk thru the connector list and
> > obtain the associated encoder. Walking thru the encoder list isn't
> > sufficient as there is no easy way from encoder to connector.
> > I don't have a strong preference either way - in the code I'm currently
> > playing around with I keep this information in struct intel_encoder.
> 
> Can't we just loop over all connectors and before we update the
> hotplug state check whether the attached intel encoder is interested
> in the hpd irq we're processing? Or do I miss something here?

No, this is exactly how I've implemented it now.

> 
> >> with POLL and HDP connectors (sometimes on the same one) - SDVO is the
> >> prime example since polling seems to work, but not too reliably. Hence we
> >> need the polling as a backup. To correctly restore those flags I guess we
> >> need a saved_polled variable in intel_connector which we need to restore
> >> when enabling the the hpd line again.
> >
> > I don't see this in the code (drm-intel-testing pulled last Friday).
> > On any connector it is either the DRM_CONNECTOR_POLL_HPD or the
> > DRM_CONNECTOR_POLL_CONNECT (mostly with the DRM_CONNECTOR_POLL_DISCONNECT flag)
> > set but not both.
> > Of course it could be done like you suggest, ie. continue polling despite
> > waiting for interrupts, but this begs the question if we should not resort
> > to polling entirely: the only benefit of doing HDP would be that we would
> > get informed about an output change more quickly.
> 
> I mean that different connectors which use the same hpd line could use
> both polling and non-polling modes since there's only one hpd line per
> sdvo encoder. So we need to be a bit careful with which part of our
> detect code handles which pieces of hw and that we don't lose anything
> when switching modes.

Ah, ok. Got it, will think about it. Thanks!

> 
> > I had sent a patch for EDID caching on the DRM level to Dave last December.
> > I received some comments and suggestions from Ville from Intel which I had
> > worked in - however I have not seen any reaction from Dave, yet.
> 
> Hm, missed that, I'll take a look again.

I had sent it on dri-devel. If you want I can send this to you again.

> 
> > Maybe you want to take a look at this. It cannot cache in all situations
> > where caching would be useful and possible. It still should do a fairly good
> > job of caching EDID extension blocks. This is because it currently
> > lacks any driver interface and thus only can do as much as you can do
> > without a deeper knowledge of what's going on on the hardware level.
> 
> Atm I'm less sure about what we really should do wrt edid caching. One
> ugly problem is boot-up, where a bunch of userspace pieces all want to
> figure out the optimal configuration, but where it's pretty pointless
> to re-query to hw all the time. So I wonder whether we shouldn't have
> temporal caching of even unreliable outputs (e.g. a few seconds), with
> an option for drivers to invalidate the cache on e.g. a hpd interrupt.

Definitely. I don't think it is unreasonable to believe that once we have
a valid EDID that this will remain valid either until we receive an event
from the hardware telling us that something has changed (hotplug event)
or we reprobe and find out that something has definitely changed or
our reprobe timeout has expired.
If there's no valid EDID it is of course reasonable to reprobe at the
earliest convenience: the situation where there's no EDID at all can
be detected very quickly.
EDID readout is a slow undertaking and EDID extension make it even
take longer.
Thus in my code I compare the EDID base block and if this hasn't changed
I use data from the cache. This of course will only work if monitors
are not able to dynamically reconfigure their EDID blocks.

> 
> Another ugly issue is when people disconnect outputs slowly so that we
> get the hpd interrupt _before_ the cable is fully unplugged. We've
> tried to fix those by checking the relevant hpd line state, but on
> noisy lines that won't really work out well (and we already have the
> regression bugs to prove it's a bad idea). So imo that entire
> caching/re-probing topic needs more thought.

Grr. Would it help to simply delay the worker a few tenth of a second so
that this will happen less likely?

Cheers,
	Egbert.

[PATCH v.2 00/12] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Egbert Eich]

I've reworked my 'hotplug interrupt storm detection'-patches and 
included most of Daniel's suggestions.
I've looked into adding EDID caching but since this requires some
larger scale changes and some changes outside of the Intel driver
it seemed to be a good idea to propose those changes at a later time.

Egbert Eich (12):
  DRM/i915: Remove valleyview_hpd_irq_setup.
  DRM/I915: Add enum hpd_pin to intel_encoder.
  DRM/i915: Convert HPD interrupts to make use of HPD pin assignment in
    encoders.
  DRM/i915: Remove i965_hpd_irq_setup.
  DRM/i915: Get rid if the 'hotplug_supported_mask' in struct
    drm_i915_private.
  DRM/i915: Add HPD IRQ storm detection.
  DRM/i915: (re)init HPD interrupt storm statistics.
  DRM/i915: Treat hpd_irq_setup() for ironake and older generations the
    same way.
  DRM/i915: Disable HPD interrupt on pin when irq storm is detected.
  DRM/i915: Add Reenable Timer to turn Hotplug Detection back on.
  DRM/i915: Add bit field to record which pins have received HPD
    events.
  DRM/i915: Only reprobe display on encoder which has received an HPD
    event.

 drivers/gpu/drm/i915/i915_drv.h   |   26 +++-
 drivers/gpu/drm/i915/i915_irq.c   |  404 ++++++++++++++++++++++++++-----------
 drivers/gpu/drm/i915/i915_reg.h   |   32 +++-
 drivers/gpu/drm/i915/intel_crt.c  |   10 +-
 drivers/gpu/drm/i915/intel_dp.c   |    8 +-
 drivers/gpu/drm/i915/intel_drv.h  |    5 +
 drivers/gpu/drm/i915/intel_hdmi.c |    8 +-
 drivers/gpu/drm/i915/intel_sdvo.c |   17 +-
 drivers/gpu/drm/i915/intel_tv.c   |    2 +-
 9 files changed, 372 insertions(+), 140 deletions(-)

-- 
1.7.7

[PATCH v.2 01/12] DRM/i915: Remove valleyview_hpd_irq_setup.

[Egbert Eich]

It's basically identical to i915_hpd_irq_setup().

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   26 +-------------------------
 1 files changed, 1 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2cd97d1..5fd3267 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2113,30 +2113,6 @@ static int valleyview_irq_postinstall(struct drm_device *dev)
 	return 0;
 }
 
-static void valleyview_hpd_irq_setup(struct drm_device *dev)
-{
-	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
-
-	/* Note HDMI and DP share bits */
-	if (dev_priv->hotplug_supported_mask & PORTB_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTB_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & PORTC_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTC_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & PORTD_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTD_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
-		hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
-		hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-		hotplug_en |= CRT_HOTPLUG_INT_EN;
-		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-	}
-
-	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
-}
-
 static void valleyview_irq_uninstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -2835,7 +2811,7 @@ void intel_irq_init(struct drm_device *dev)
 		dev->driver->irq_uninstall = valleyview_irq_uninstall;
 		dev->driver->enable_vblank = valleyview_enable_vblank;
 		dev->driver->disable_vblank = valleyview_disable_vblank;
-		dev_priv->display.hpd_irq_setup = valleyview_hpd_irq_setup;
+		dev_priv->display.hpd_irq_setup = i915_hpd_irq_setup;
 	} else if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
 		/* Share pre & uninstall handlers with ILK/SNB */
 		dev->driver->irq_handler = ivybridge_irq_handler;
-- 
1.7.7

[PATCH v.2 02/12] DRM/I915: Add enum hpd_pin to intel_encoder.

[Egbert Eich]

To clean up hotplug support we add a new enum to intel_encoder:
enum hpd_pin. It allows the encoder to request a hpd line but leave
the details which IRQ is responsible on which chipset generation
to i915_irq.c.
This way requesting hotplug support will become really simple on
the encoder/connector level.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h   |   13 +++++++++++++
 drivers/gpu/drm/i915/intel_crt.c  |    2 ++
 drivers/gpu/drm/i915/intel_dp.c   |    4 ++++
 drivers/gpu/drm/i915/intel_drv.h  |    1 +
 drivers/gpu/drm/i915/intel_hdmi.c |    4 ++++
 drivers/gpu/drm/i915/intel_sdvo.c |    3 +++
 6 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e95337c..316747a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -86,6 +86,19 @@ enum port {
 };
 #define port_name(p) ((p) + 'A')
 
+enum hpd_pin {
+	HPD_NONE = 0,
+	HPD_PORT_A = HPD_NONE, /* PORT_A is internal */
+	HPD_TV = HPD_NONE,     /* TV is known to be unreliable */
+	HPD_CRT,
+	HPD_SDVO_B,
+	HPD_SDVO_C,
+	HPD_PORT_B,
+	HPD_PORT_C,
+	HPD_PORT_D,
+	HPD_NUM_PINS
+};
+
 #define I915_GEM_GPU_DOMAINS \
 	(I915_GEM_DOMAIN_RENDER | \
 	 I915_GEM_DOMAIN_SAMPLER | \
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index cfc9687..de43cab 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -777,6 +777,8 @@ void intel_crt_init(struct drm_device *dev)
 
 	crt->base.disable = intel_disable_crt;
 	crt->base.enable = intel_enable_crt;
+	if (I915_HAS_HOTPLUG(dev))
+		crt->base.hpd_pin = HPD_CRT;
 	if (HAS_DDI(dev))
 		crt->base.get_hw_state = intel_ddi_get_hw_state;
 	else
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 7b8bfe8..549933a 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2835,18 +2835,22 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 	/* Set up the DDC bus. */
 	switch (port) {
 	case PORT_A:
+		intel_encoder->hpd_pin = HPD_PORT_A;
 		name = "DPDDC-A";
 		break;
 	case PORT_B:
 		dev_priv->hotplug_supported_mask |= PORTB_HOTPLUG_INT_STATUS;
+		intel_encoder->hpd_pin = HPD_PORT_B;
 		name = "DPDDC-B";
 		break;
 	case PORT_C:
 		dev_priv->hotplug_supported_mask |= PORTC_HOTPLUG_INT_STATUS;
+		intel_encoder->hpd_pin = HPD_PORT_C;
 		name = "DPDDC-C";
 		break;
 	case PORT_D:
 		dev_priv->hotplug_supported_mask |= PORTD_HOTPLUG_INT_STATUS;
+		intel_encoder->hpd_pin = HPD_PORT_D;
 		name = "DPDDC-D";
 		break;
 	default:
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 005a91f..c9003bd 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -168,6 +168,7 @@ struct intel_encoder {
 	 * it is connected to in the pipe parameter. */
 	bool (*get_hw_state)(struct intel_encoder *, enum pipe *pipe);
 	int crtc_mask;
+	enum hpd_pin hpd_pin;
 };
 
 struct intel_panel {
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 5a6138c..8cd6bc1 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1022,17 +1022,21 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
 	switch (port) {
 	case PORT_B:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPB;
+		intel_encoder->hpd_pin = HPD_PORT_B;
 		dev_priv->hotplug_supported_mask |= PORTB_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_C:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPC;
+		intel_encoder->hpd_pin = HPD_PORT_C;
 		dev_priv->hotplug_supported_mask |= PORTC_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_D:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPD;
+		intel_encoder->hpd_pin = HPD_PORT_D;
 		dev_priv->hotplug_supported_mask |= PORTD_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_A:
+		intel_encoder->hpd_pin = HPD_PORT_A;
 		/* Internal port only for eDP. */
 	default:
 		BUG();
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index f01063a..cf57705 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -2780,6 +2780,9 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
 			SDVOB_HOTPLUG_INT_STATUS_I915 : SDVOC_HOTPLUG_INT_STATUS_I915;
 	}
 
+	if (intel_sdvo->hotplug_active)
+		intel_encoder->hpd_pin = HPD_SDVO_B ? HPD_SDVO_B : HPD_SDVO_C;
+
 	drm_encoder_helper_add(&intel_encoder->base, &intel_sdvo_helper_funcs);
 
 	intel_encoder->disable = intel_disable_sdvo;
-- 
1.7.7

[PATCH v.2 03/12] DRM/i915: Convert HPD interrupts to make use of HPD pin assignment in encoders.

[Egbert Eich]

This allows to enable HPD interrupts for individual pins to only receive
hotplug events from lines which are connected and working.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |  160 ++++++++++++++++++++++++--------------
 drivers/gpu/drm/i915/i915_reg.h |   32 ++++++++-
 2 files changed, 132 insertions(+), 60 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 5fd3267..306cd79 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -36,6 +36,68 @@
 #include "i915_trace.h"
 #include "intel_drv.h"
 
+static const u32 hpd_ibx[] = {
+	0, /* HPD_NONE */
+	SDE_CRT_HOTPLUG, /* HPD_CRT */
+	SDE_SDVOB_HOTPLUG, /* HPD_SDVO_B */
+	0, /* HPD_SDVO_C */
+	SDE_PORTB_HOTPLUG, /* HPD_PORT_B */
+	SDE_PORTC_HOTPLUG, /* HPD_PORT_C */
+	SDE_PORTD_HOTPLUG  /* HPD_PORT_D */
+};
+
+static const u32 hpd_cpt[] = {
+	0, /* HPD_NONE */
+	SDE_CRT_HOTPLUG_CPT, /* HPD_CRT */
+	0, /* HPD_SDVO_B */
+	0, /* HPD_SDVO_C */
+	SDE_PORTB_HOTPLUG_CPT, /* HPD_PORT_B */
+	SDE_PORTC_HOTPLUG_CPT, /* HPD_PORT_C */
+	SDE_PORTD_HOTPLUG_CPT  /* HPD_PORT_D */
+};
+
+static const u32 hpd_mask_i915[] = {
+	0, /* HPD_NONE */
+	CRT_HOTPLUG_INT_EN, /* HPD_CRT */
+	SDVOB_HOTPLUG_INT_EN, /* HPD_SDVO_B */
+	SDVOC_HOTPLUG_INT_EN, /* HPD_SDVO_C */
+	PORTB_HOTPLUG_INT_EN, /* HPD_PORT_B */
+	PORTC_HOTPLUG_INT_EN, /* HPD_PORT_C */
+	PORTD_HOTPLUG_INT_EN  /* HPD_PORT_D */
+};
+
+static const u32 hpd_status_gen4[] = {
+	0, /* HPD_NONE */
+	CRT_HOTPLUG_INT_STATUS, /* HPD_CRT */
+	SDVOB_HOTPLUG_INT_STATUS_G4X, /* HPD_SDVO_B */
+	SDVOC_HOTPLUG_INT_STATUS_G4X, /* HPD_SDVO_C */
+	PORTB_HOTPLUG_INT_STATUS, /* HPD_PORT_B */
+	PORTC_HOTPLUG_INT_STATUS, /* HPD_PORT_C */
+	PORTD_HOTPLUG_INT_STATUS /* HPD_PORT_D */
+};
+
+static const u32 hpd_status_i965[] = {
+	 0,  /* HPD_NONE */
+	 CRT_HOTPLUG_INT_STATUS,  /* HPD_CRT */
+	 SDVOB_HOTPLUG_INT_STATUS_I965,  /* HPD_SDVO_B */
+	 SDVOC_HOTPLUG_INT_STATUS_I965,  /* HPD_SDVO_C */
+	 PORTB_HOTPLUG_INT_STATUS,  /* HPD_PORT_B */
+	 PORTC_HOTPLUG_INT_STATUS,  /* HPD_PORT_C */
+	 PORTD_HOTPLUG_INT_STATUS   /* HPD_PORT_D */
+};
+
+static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
+	0,  /* HPD_NONE */
+	CRT_HOTPLUG_INT_STATUS,  /* HPD_CRT */
+	SDVOB_HOTPLUG_INT_STATUS_I915,  /* HPD_SDVO_B */
+	SDVOC_HOTPLUG_INT_STATUS_I915,  /* HPD_SDVO_C */
+	PORTB_HOTPLUG_INT_STATUS,  /* HPD_PORT_B */
+	PORTC_HOTPLUG_INT_STATUS,  /* HPD_PORT_C */
+	PORTD_HOTPLUG_INT_STATUS   /* HPD_PORT_D */
+};
+
+
+
 /* For display hotplug interrupt */
 static void
 ironlake_enable_display_irq(drm_i915_private_t *dev_priv, u32 mask)
@@ -596,7 +658,7 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 
@@ -1940,17 +2002,21 @@ static void ibx_enable_hotplug(struct drm_device *dev)
 static void ibx_irq_postinstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 mask;
-
-	if (HAS_PCH_IBX(dev))
-		mask = SDE_HOTPLUG_MASK |
-		       SDE_GMBUS |
-		       SDE_AUX_MASK;
-	else
-		mask = SDE_HOTPLUG_MASK_CPT |
-		       SDE_GMBUS_CPT |
-		       SDE_AUX_MASK_CPT;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct intel_encoder *intel_encoder;
+	u32 mask = I915_READ(SDEIER);
 
+	if (HAS_PCH_IBX(dev)) {
+		mask &= ~SDE_HOTPLUG_MASK;
+		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
+			mask |= hpd_ibx[intel_encoder->hpd_pin];
+		mask |= SDE_GMBUS | SDE_AUX_MASK;
+	} else {
+		mask &= ~SDE_HOTPLUG_MASK_CPT;
+		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
+			mask |= hpd_cpt[intel_encoder->hpd_pin];
+		mask |= SDE_GMBUS_CPT | SDE_AUX_MASK_CPT;
+	}
 	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
 	I915_WRITE(SDEIMR, ~mask);
 	I915_WRITE(SDEIER, mask);
@@ -2360,26 +2426,16 @@ static int i915_irq_postinstall(struct drm_device *dev)
 
 static void i915_hpd_irq_setup(struct drm_device *dev)
 {
-	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 hotplug_en;
-
 	if (I915_HAS_HOTPLUG(dev)) {
-		hotplug_en = I915_READ(PORT_HOTPLUG_EN);
+		drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+		struct drm_mode_config *mode_config = &dev->mode_config;
+		struct intel_encoder *encoder;
+		u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
 
-		if (dev_priv->hotplug_supported_mask & PORTB_HOTPLUG_INT_STATUS)
-			hotplug_en |= PORTB_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & PORTC_HOTPLUG_INT_STATUS)
-			hotplug_en |= PORTC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & PORTD_HOTPLUG_INT_STATUS)
-			hotplug_en |= PORTD_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-			hotplug_en |= CRT_HOTPLUG_INT_EN;
-			hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-		}
+		hotplug_en &= ~HOTPLUG_INT_EN_MASK;
+		list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
+			hotplug_en |= hpd_mask_i915[encoder->hpd_pin];
+		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
 
 		/* Ignore TV since it's buggy */
 
@@ -2443,7 +2499,7 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 
@@ -2596,38 +2652,22 @@ static int i965_irq_postinstall(struct drm_device *dev)
 static void i965_hpd_irq_setup(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct intel_encoder *encoder;
 	u32 hotplug_en;
 
 	/* Note HDMI and DP share hotplug bits */
 	hotplug_en = 0;
-	if (dev_priv->hotplug_supported_mask & PORTB_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTB_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & PORTC_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTC_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & PORTD_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTD_HOTPLUG_INT_EN;
-	if (IS_G4X(dev)) {
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_G4X)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_G4X)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	} else {
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I965)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I965)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	}
-	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-		hotplug_en |= CRT_HOTPLUG_INT_EN;
-
-		/* Programming the CRT detection parameters tends
-		   to generate a spurious hotplug event about three
-		   seconds later.  So just do it once.
-		   */
-		if (IS_G4X(dev))
-			hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
-		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-	}
+	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
+		/* enable bits are the same for all generations */
+		hotplug_en |= hpd_mask_i915[encoder->hpd_pin];
+	/* Programming the CRT detection parameters tends
+	   to generate a spurious hotplug event about three
+	   seconds later.  So just do it once.
+	*/
+	if (IS_G4X(dev))
+		hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
+	hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
 
 	/* Ignore TV since it's buggy */
 
@@ -2690,7 +2730,9 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_status & (IS_G4X(dev) ?
+					      HOTPLUG_INT_STATUS_G4X :
+					      HOTPLUG_INT_STATUS_I965))
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 527b664..c3d2c01 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1637,6 +1637,12 @@
 #define   SDVOC_HOTPLUG_INT_EN			(1 << 25)
 #define   TV_HOTPLUG_INT_EN			(1 << 18)
 #define   CRT_HOTPLUG_INT_EN			(1 << 9)
+#define HOTPLUG_INT_EN_MASK			(PORTB_HOTPLUG_INT_EN | \
+						 PORTC_HOTPLUG_INT_EN | \
+						 PORTD_HOTPLUG_INT_EN | \
+						 SDVOC_HOTPLUG_INT_EN | \
+						 SDVOB_HOTPLUG_INT_EN | \
+						 CRT_HOTPLUG_INT_EN)
 #define   CRT_HOTPLUG_FORCE_DETECT		(1 << 3)
 #define CRT_HOTPLUG_ACTIVATION_PERIOD_32	(0 << 8)
 /* must use period 64 on GM45 according to docs */
@@ -1675,6 +1681,26 @@
 #define   SDVOB_HOTPLUG_INT_STATUS_I965		(3 << 2)
 #define   SDVOC_HOTPLUG_INT_STATUS_I915		(1 << 7)
 #define   SDVOB_HOTPLUG_INT_STATUS_I915		(1 << 6)
+#define   HOTPLUG_INT_STATUS_G4X		(CRT_HOTPLUG_INT_STATUS | \
+						 SDVOB_HOTPLUG_INT_STATUS_G4X | \
+						 SDVOC_HOTPLUG_INT_STATUS_G4X | \
+						 PORTB_HOTPLUG_INT_STATUS | \
+						 PORTC_HOTPLUG_INT_STATUS | \
+						 PORTD_HOTPLUG_INT_STATUS)
+
+#define HOTPLUG_INT_STATUS_I965			(CRT_HOTPLUG_INT_STATUS | \
+						 SDVOB_HOTPLUG_INT_STATUS_I965 | \
+						 SDVOC_HOTPLUG_INT_STATUS_I965 | \
+						 PORTB_HOTPLUG_INT_STATUS | \
+						 PORTC_HOTPLUG_INT_STATUS | \
+						 PORTD_HOTPLUG_INT_STATUS)
+
+#define HOTPLUG_INT_STATUS_I915			(CRT_HOTPLUG_INT_STATUS | \
+						 SDVOB_HOTPLUG_INT_STATUS_I915 | \
+						 SDVOC_HOTPLUG_INT_STATUS_I915 | \
+						 PORTB_HOTPLUG_INT_STATUS | \
+						 PORTC_HOTPLUG_INT_STATUS | \
+						 PORTD_HOTPLUG_INT_STATUS)
 
 /* SDVO port control */
 #define SDVOB			0x61140
@@ -3508,7 +3534,11 @@
 #define SDE_PORTC_HOTPLUG       (1 << 9)
 #define SDE_PORTB_HOTPLUG       (1 << 8)
 #define SDE_SDVOB_HOTPLUG       (1 << 6)
-#define SDE_HOTPLUG_MASK	(0xf << 8)
+#define SDE_HOTPLUG_MASK        (SDE_CRT_HOTPLUG | \
+				 SDE_SDVOB_HOTPLUG |	\
+				 SDE_PORTB_HOTPLUG |	\
+				 SDE_PORTC_HOTPLUG |	\
+				 SDE_PORTD_HOTPLUG)
 #define SDE_TRANSB_CRC_DONE	(1 << 5)
 #define SDE_TRANSB_CRC_ERR	(1 << 4)
 #define SDE_TRANSB_FIFO_UNDER	(1 << 3)
-- 
1.7.7

[PATCH v.2 04/12] DRM/i915: Remove i965_hpd_irq_setup.

[Egbert Eich]

After
"Convert HPD interrupts to make use of HPD pin assignment in encoders."
This function is now basically the same as i915_hpd_irq_setup().

Consolidating both functions in one requires one more check for
I915_HAS_HOTPLUG(dev) in the i965 code path and one more check for
IS_G4X(dev) in the i915 code path. These are considered harmless.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   53 +++++++++++++-------------------------
 1 files changed, 18 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 306cd79..c6ae7ae 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2424,25 +2424,6 @@ static int i915_irq_postinstall(struct drm_device *dev)
 	return 0;
 }
 
-static void i915_hpd_irq_setup(struct drm_device *dev)
-{
-	if (I915_HAS_HOTPLUG(dev)) {
-		drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-		struct drm_mode_config *mode_config = &dev->mode_config;
-		struct intel_encoder *encoder;
-		u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
-
-		hotplug_en &= ~HOTPLUG_INT_EN_MASK;
-		list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
-			hotplug_en |= hpd_mask_i915[encoder->hpd_pin];
-		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-
-		/* Ignore TV since it's buggy */
-
-		I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
-	}
-}
-
 static irqreturn_t i915_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
@@ -2649,29 +2630,31 @@ static int i965_irq_postinstall(struct drm_device *dev)
 	return 0;
 }
 
-static void i965_hpd_irq_setup(struct drm_device *dev)
+static void i915_hpd_irq_setup(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	struct drm_mode_config *mode_config = &dev->mode_config;
 	struct intel_encoder *encoder;
 	u32 hotplug_en;
 
-	/* Note HDMI and DP share hotplug bits */
-	hotplug_en = 0;
-	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
+	if (I915_HAS_HOTPLUG(dev)) {
+		hotplug_en = I915_READ(PORT_HOTPLUG_EN);
+		hotplug_en &= ~HOTPLUG_INT_EN_MASK;
+		/* Note HDMI and DP share hotplug bits */
 		/* enable bits are the same for all generations */
-		hotplug_en |= hpd_mask_i915[encoder->hpd_pin];
-	/* Programming the CRT detection parameters tends
-	   to generate a spurious hotplug event about three
-	   seconds later.  So just do it once.
-	*/
-	if (IS_G4X(dev))
-		hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
-	hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-
-	/* Ignore TV since it's buggy */
+		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
+			hotplug_en |= hpd_mask_i915[intel_encoder->hpd_pin];
+		/* Programming the CRT detection parameters tends
+		   to generate a spurious hotplug event about three
+		   seconds later.  So just do it once.
+		*/
+		if (IS_G4X(dev))
+			hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
+		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
 
-	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+		/* Ignore TV since it's buggy */
+		I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+	}
 }
 
 static irqreturn_t i965_irq_handler(int irq, void *arg)
@@ -2886,7 +2869,7 @@ void intel_irq_init(struct drm_device *dev)
 			dev->driver->irq_postinstall = i965_irq_postinstall;
 			dev->driver->irq_uninstall = i965_irq_uninstall;
 			dev->driver->irq_handler = i965_irq_handler;
-			dev_priv->display.hpd_irq_setup = i965_hpd_irq_setup;
+			dev_priv->display.hpd_irq_setup = i915_hpd_irq_setup;
 		}
 		dev->driver->enable_vblank = i915_enable_vblank;
 		dev->driver->disable_vblank = i915_disable_vblank;
-- 
1.7.7

[PATCH v.2 05/12] DRM/i915: Get rid if the 'hotplug_supported_mask' in struct drm_i915_private.

[Egbert Eich]

Now since we have replaced the bits to show interest in hotplug IRQs
we can go and nuke the 'hotplug_supported_mask'.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h   |    1 -
 drivers/gpu/drm/i915/intel_crt.c  |    2 --
 drivers/gpu/drm/i915/intel_dp.c   |    3 ---
 drivers/gpu/drm/i915/intel_hdmi.c |    3 ---
 drivers/gpu/drm/i915/intel_sdvo.c |    9 +++------
 5 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 316747a..d8604a6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -922,7 +922,6 @@ typedef struct drm_i915_private {
 	u32 irq_mask;
 	u32 gt_irq_mask;
 
-	u32 hotplug_supported_mask;
 	struct work_struct hotplug_work;
 	bool enable_hotplug_processing;
 
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index de43cab..5654583 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -800,8 +800,6 @@ void intel_crt_init(struct drm_device *dev)
 	 */
 	crt->force_hotplug_required = 0;
 
-	dev_priv->hotplug_supported_mask |= CRT_HOTPLUG_INT_STATUS;
-
 	/*
 	 * TODO: find a proper way to discover whether we need to set the the
 	 * polarity and link reversal bits or not, instead of relying on the
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 549933a..5a77d40 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2839,17 +2839,14 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 		name = "DPDDC-A";
 		break;
 	case PORT_B:
-		dev_priv->hotplug_supported_mask |= PORTB_HOTPLUG_INT_STATUS;
 		intel_encoder->hpd_pin = HPD_PORT_B;
 		name = "DPDDC-B";
 		break;
 	case PORT_C:
-		dev_priv->hotplug_supported_mask |= PORTC_HOTPLUG_INT_STATUS;
 		intel_encoder->hpd_pin = HPD_PORT_C;
 		name = "DPDDC-C";
 		break;
 	case PORT_D:
-		dev_priv->hotplug_supported_mask |= PORTD_HOTPLUG_INT_STATUS;
 		intel_encoder->hpd_pin = HPD_PORT_D;
 		name = "DPDDC-D";
 		break;
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 8cd6bc1..e48452a 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1023,17 +1023,14 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
 	case PORT_B:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPB;
 		intel_encoder->hpd_pin = HPD_PORT_B;
-		dev_priv->hotplug_supported_mask |= PORTB_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_C:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPC;
 		intel_encoder->hpd_pin = HPD_PORT_C;
-		dev_priv->hotplug_supported_mask |= PORTC_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_D:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPD;
 		intel_encoder->hpd_pin = HPD_PORT_D;
-		dev_priv->hotplug_supported_mask |= PORTD_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_A:
 		intel_encoder->hpd_pin = HPD_PORT_A;
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index cf57705..d362dd5 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -2780,6 +2780,9 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
 			SDVOB_HOTPLUG_INT_STATUS_I915 : SDVOC_HOTPLUG_INT_STATUS_I915;
 	}
 
+	/* Only enable the hotplug irq if we need it, to work around noisy
+	 * hotplug lines.
+	 */
 	if (intel_sdvo->hotplug_active)
 		intel_encoder->hpd_pin = HPD_SDVO_B ? HPD_SDVO_B : HPD_SDVO_C;
 
@@ -2811,12 +2814,6 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
 	 */
 	intel_sdvo->base.cloneable = false;
 
-	/* Only enable the hotplug irq if we need it, to work around noisy
-	 * hotplug lines.
-	 */
-	if (intel_sdvo->hotplug_active)
-		dev_priv->hotplug_supported_mask |= hotplug_mask;
-
 	intel_sdvo_select_ddc_bus(dev_priv, intel_sdvo, sdvo_reg);
 
 	/* Set the input timing to the screen. Assume always input 0. */
-- 
1.7.7

[PATCH v.2 06/12] DRM/i915: Add HPD IRQ storm detection.

[Egbert Eich]

Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
fires more than 5 times / sec).
Mask out this specific interrupt and revert to polling on the associated
output.
Rationale:
Despite of the many attempts to fix the problem with noisy hotplug
interrupt lines we are still seeing systems which have issues:
Once cause of noise seems to be bad routing of the hotplug line
on the board: cross talk from other signals seems to cause erronous
hotplug interrupts. This has been documented as an erratum for the
the i945GM chipset and thus hotplug support was disabled for this
chipset model but others seem to have this problem, too.

We have seen this issue on a G35 motherboard for example:
Even different motherboards of the same model seem to behave
differently: while some only see only around 10-100 interrupts/s
others seem to see 5k or more.
We've also observed a dependency on the selected video mode.

Also on certain laptops interrupt noise seems to occur duing
battery charging when the battery is at a certain charge levels.

Thus we add a simple algorithm here that detects an 'interrupt storm'
condition.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    9 +++++
 drivers/gpu/drm/i915/i915_irq.c |   63 +++++++++++++++++++++++++++++++-------
 2 files changed, 60 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d8604a6..6ca742d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1059,6 +1059,15 @@ typedef struct drm_i915_private {
 	/* Old dri1 support infrastructure, beware the dragons ya fools entering
 	 * here! */
 	struct i915_dri1_state dri1;
+	struct {
+		unsigned long hpd_last_jiffies;
+		int hpd_cnt;
+		enum {
+			HPD_ENABLED = 0,
+			HPD_DISABLED = 1,
+			HPD_MARK_DISABLED = 2
+		} hpd_mark;
+	} hpd_stats[HPD_NUM_PINS];
 } drm_i915_private_t;
 
 /* Iterate over initialised rings */
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index c6ae7ae..08a0934 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -587,6 +587,34 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
 	queue_work(dev_priv->wq, &dev_priv->rps.work);
 }
 
+static inline void hotplug_irq_storm_detect(struct drm_device *dev,
+					    u32 hotplug_trigger,
+					    const u32 *hpd)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	unsigned long irqflags;
+	int i;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	for (i = 1; i < HPD_NUM_PINS; i++) {
+		if ((hpd[i] & hotplug_trigger) &&
+		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
+			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
+			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
+				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
+				dev_priv->hpd_stats[i].hpd_cnt = 0;
+			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
+				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
+				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
+			} else
+				dev_priv->hpd_stats[i].hpd_cnt++;
+		}
+	}
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
 static void gmbus_irq_handler(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -655,13 +683,15 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
-			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
@@ -685,10 +715,12 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
 
-	if (pch_iir & SDE_HOTPLUG_MASK)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK) >>
@@ -731,10 +763,12 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
 
-	if (pch_iir & SDE_HOTPLUG_MASK_CPT)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
@@ -2477,13 +2511,15 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 		if ((I915_HAS_HOTPLUG(dev)) &&
 		    (iir & I915_DISPLAY_PORT_INTERRUPT)) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			POSTING_READ(PORT_HOTPLUG_STAT);
 		}
@@ -2710,15 +2746,18 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & (IS_G4X(dev) ?
+								  HOTPLUG_INT_STATUS_G4X :
+								  HOTPLUG_INT_STATUS_I965);
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & (IS_G4X(dev) ?
-					      HOTPLUG_INT_STATUS_G4X :
-					      HOTPLUG_INT_STATUS_I965))
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger,
+							 IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
-- 
1.7.7

[PATCH v.2 07/12] DRM/i915: (re)init HPD interrupt storm statistics.

[Egbert Eich]

When an encoder is shared on several connectors there is only
one hotplug line, thus this line needs to be shared among these
connectors.
If HPD detect only works reliably on a subset of those connectors,
we want to poll the others. Thus we need to make sure that storm
detection doesn't mess up the settings for those connectors.
Therefore we store the settings in the intel_connector struct and
restore them from there.
If nothing is set but the encoder has a hpd_pin set we assume this
connector is hotplug capable.
On init/reset we make sure the polled state of the connectors
is (re)set to the default value, the HPD interrupts are marked
enabled.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c   |   13 +++++++++++++
 drivers/gpu/drm/i915/intel_crt.c  |    6 ++----
 drivers/gpu/drm/i915/intel_dp.c   |    1 -
 drivers/gpu/drm/i915/intel_drv.h  |    4 ++++
 drivers/gpu/drm/i915/intel_hdmi.c |    1 -
 drivers/gpu/drm/i915/intel_sdvo.c |    5 ++---
 drivers/gpu/drm/i915/intel_tv.c   |    2 +-
 7 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 08a0934..d1ccff7 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2918,7 +2918,20 @@ void intel_irq_init(struct drm_device *dev)
 void intel_hpd_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct drm_connector *connector;
+	int i;
 
+	for (i = 1; i < HPD_NUM_PINS; i++) {
+		dev_priv->hpd_stats[i].hpd_cnt = 0;
+		dev_priv->hpd_stats[i].hpd_mark = HPD_ENABLED;
+	}
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		struct intel_connector *intel_connector = to_intel_connector(connector);
+		connector->polled = intel_connector->polled;
+		if (!connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE)
+			connector->polled = DRM_CONNECTOR_POLL_HPD;
+	}
 	if (dev_priv->display.hpd_irq_setup)
 		dev_priv->display.hpd_irq_setup(dev);
 }
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 5654583..4318f3e 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -790,10 +790,8 @@ void intel_crt_init(struct drm_device *dev)
 
 	drm_sysfs_connector_add(connector);
 
-	if (I915_HAS_HOTPLUG(dev))
-		connector->polled = DRM_CONNECTOR_POLL_HPD;
-	else
-		connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	if (!I915_HAS_HOTPLUG(dev))
+		intel_connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 
 	/*
 	 * Configure the automatic hotplug detection stuff
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 5a77d40..66134d1 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2816,7 +2816,6 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 	drm_connector_init(dev, connector, &intel_dp_connector_funcs, type);
 	drm_connector_helper_add(connector, &intel_dp_connector_helper_funcs);
 
-	connector->polled = DRM_CONNECTOR_POLL_HPD;
 	connector->interlace_allowed = true;
 	connector->doublescan_allowed = 0;
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index c9003bd..142f40a 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -198,6 +198,10 @@ struct intel_connector {
 
 	/* Cached EDID for eDP and LVDS. May hold ERR_PTR for invalid EDID. */
 	struct edid *edid;
+
+	/* since POLL and HPD connectors may use the same HPD line keep the native
+	   state of connector->polled in case hotplug storm detection changes it */
+	u8 polled;
 };
 
 struct intel_crtc {
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index e48452a..82c9b9b 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1015,7 +1015,6 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
 			   DRM_MODE_CONNECTOR_HDMIA);
 	drm_connector_helper_add(connector, &intel_hdmi_connector_helper_funcs);
 
-	connector->polled = DRM_CONNECTOR_POLL_HPD;
 	connector->interlace_allowed = 1;
 	connector->doublescan_allowed = 0;
 
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index d362dd5..30635c6 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -2270,7 +2270,6 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
 	connector = &intel_connector->base;
 	if (intel_sdvo_get_hotplug_support(intel_sdvo) &
 		intel_sdvo_connector->output_flag) {
-		connector->polled = DRM_CONNECTOR_POLL_HPD;
 		intel_sdvo->hotplug_active |= intel_sdvo_connector->output_flag;
 		/* Some SDVO devices have one-shot hotplug interrupts.
 		 * Ensure that they get re-enabled when an interrupt happens.
@@ -2278,7 +2277,7 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
 		intel_encoder->hot_plug = intel_sdvo_enable_hotplug;
 		intel_sdvo_enable_hotplug(intel_encoder);
 	} else {
-		connector->polled = DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
+		intel_connector->polled = DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
 	}
 	encoder->encoder_type = DRM_MODE_ENCODER_TMDS;
 	connector->connector_type = DRM_MODE_CONNECTOR_DVID;
@@ -2347,7 +2346,7 @@ intel_sdvo_analog_init(struct intel_sdvo *intel_sdvo, int device)
 
 	intel_connector = &intel_sdvo_connector->base;
 	connector = &intel_connector->base;
-	connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	intel_connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 	encoder->encoder_type = DRM_MODE_ENCODER_DAC;
 	connector->connector_type = DRM_MODE_CONNECTOR_VGA;
 
diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index 984a113..a5a3fc0 100644
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -1613,7 +1613,7 @@ intel_tv_init(struct drm_device *dev)
 	 *
 	 * More recent chipsets favour HDMI rather than integrated S-Video.
 	 */
-	connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	intel_connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 
 	drm_connector_init(dev, connector, &intel_tv_connector_funcs,
 			   DRM_MODE_CONNECTOR_SVIDEO);
-- 
1.7.7

[PATCH v.2 08/12] DRM/i915: Treat hpd_irq_setup() for ironake and older generations the same way.

[Egbert Eich]

When switching to enabling HPD IRQs only for lines where needed and supported
this will ensure that the right lines will be enabled on all generations when
intel_hpd_init() is called.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d1ccff7..e0cf629 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2033,7 +2033,7 @@ static void ibx_enable_hotplug(struct drm_device *dev)
 	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
 }
 
-static void ibx_irq_postinstall(struct drm_device *dev)
+static void ibx_hpd_irq_setup(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	struct drm_mode_config *mode_config = &dev->mode_config;
@@ -2055,8 +2055,6 @@ static void ibx_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(SDEIMR, ~mask);
 	I915_WRITE(SDEIER, mask);
 	POSTING_READ(SDEIER);
-
-	ibx_enable_hotplug(dev);
 }
 
 static int ironlake_irq_postinstall(struct drm_device *dev)
@@ -2094,7 +2092,7 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(GTIER, render_irqs);
 	POSTING_READ(GTIER);
 
-	ibx_irq_postinstall(dev);
+	ibx_enable_hotplug(dev);
 
 	if (IS_IRONLAKE_M(dev)) {
 		/* Clear & enable PCU event interrupts */
@@ -2140,7 +2138,7 @@ static int ivybridge_irq_postinstall(struct drm_device *dev)
 	I915_WRITE(GTIER, render_irqs);
 	POSTING_READ(GTIER);
 
-	ibx_irq_postinstall(dev);
+	ibx_enable_hotplug(dev);
 
 	return 0;
 }
@@ -2884,6 +2882,7 @@ void intel_irq_init(struct drm_device *dev)
 		dev->driver->irq_uninstall = ironlake_irq_uninstall;
 		dev->driver->enable_vblank = ivybridge_enable_vblank;
 		dev->driver->disable_vblank = ivybridge_disable_vblank;
+		dev_priv->display.hpd_irq_setup = ibx_hpd_irq_setup;
 	} else if (HAS_PCH_SPLIT(dev)) {
 		dev->driver->irq_handler = ironlake_irq_handler;
 		dev->driver->irq_preinstall = ironlake_irq_preinstall;
@@ -2891,6 +2890,7 @@ void intel_irq_init(struct drm_device *dev)
 		dev->driver->irq_uninstall = ironlake_irq_uninstall;
 		dev->driver->enable_vblank = ironlake_enable_vblank;
 		dev->driver->disable_vblank = ironlake_disable_vblank;
+		dev_priv->display.hpd_irq_setup = ibx_hpd_irq_setup;
 	} else {
 		if (INTEL_INFO(dev)->gen == 2) {
 			dev->driver->irq_preinstall = i8xx_irq_preinstall;
-- 
1.7.7

[PATCH v.2 09/12] DRM/i915: Disable HPD interrupt on pin when irq storm is detected.

[Egbert Eich]

This patch disables hotplug interrupts if an 'interrupt storm'
has been detected.
Noise on the interrupt line renders the hotplug interrupt useless:
each hotplug event causes the devices to be rescanned which will
will only increase the system load.
Thus disable the hotplug interrupts and fall back to periodic
device polling.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   69 ++++++++++++++++++++++++++++++---------
 1 files changed, 53 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e0cf629..8878fdd 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -96,7 +96,8 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 	PORTD_HOTPLUG_INT_STATUS   /* HPD_PORT_D */
 };
 
-
+static void ibx_hpd_irq_setup(struct drm_device *dev);
+static void i915_hpd_irq_setup(struct drm_device *dev);
 
 /* For display hotplug interrupt */
 static void
@@ -347,7 +348,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
 						    hotplug_work);
 	struct drm_device *dev = dev_priv->dev;
 	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct intel_encoder *encoder;
+	struct intel_connector *intel_connector;
+	struct intel_encoder *intel_encoder;
+	struct drm_connector *connector;
+	unsigned long irqflags;
+	bool connector_disabled = false;
 
 	/* HPD irq before everything is fully set up. */
 	if (!dev_priv->enable_hotplug_processing)
@@ -356,9 +361,29 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	mutex_lock(&mode_config->mutex);
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
-	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
-		if (encoder->hot_plug)
-			encoder->hot_plug(encoder);
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		intel_connector = to_intel_connector(connector);
+		intel_encoder = intel_connector->encoder;
+		if (intel_encoder->hpd_pin > HPD_NONE &&
+		    dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_MARK_DISABLED &&
+		    connector->polled == DRM_CONNECTOR_POLL_HPD) {
+			pr_warn("HPD interrupt storm detected on connector %s disabling\n",
+				drm_get_connector_name(connector));
+			dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark = HPD_DISABLED;
+			connector->polled = DRM_CONNECTOR_POLL_CONNECT
+				| DRM_CONNECTOR_POLL_DISCONNECT;
+			connector_disabled = true;
+		}
+	}
+	if (connector_disabled)
+		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+	list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
+		if (intel_encoder->hot_plug)
+			intel_encoder->hot_plug(encoder);
 
 	mutex_unlock(&mode_config->mutex);
 
@@ -587,13 +612,14 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
 	queue_work(dev_priv->wq, &dev_priv->rps.work);
 }
 
-static inline void hotplug_irq_storm_detect(struct drm_device *dev,
+static inline bool hotplug_irq_storm_detect(struct drm_device *dev,
 					    u32 hotplug_trigger,
 					    const u32 *hpd)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	unsigned long irqflags;
 	int i;
+	bool ret = false;
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 
@@ -607,12 +633,15 @@ static inline void hotplug_irq_storm_detect(struct drm_device *dev,
 			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
 				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
 				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
+				ret = true;
 			} else
 				dev_priv->hpd_stats[i].hpd_cnt++;
 		}
 	}
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+	return ret;
 }
 
 static void gmbus_irq_handler(struct drm_device *dev)
@@ -688,7 +717,8 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
+				if( hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915))
+					i915_hpd_irq_setup(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
@@ -718,7 +748,8 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
 
 	if (hotplug_trigger) {
-		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
+		if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx))
+			ibx_hpd_irq_setup(dev);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
 	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
@@ -766,7 +797,8 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
 
 	if (hotplug_trigger) {
-		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
+		if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt))
+			ibx_hpd_irq_setup(dev);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
 	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
@@ -2043,12 +2075,14 @@ static void ibx_hpd_irq_setup(struct drm_device *dev)
 	if (HAS_PCH_IBX(dev)) {
 		mask &= ~SDE_HOTPLUG_MASK;
 		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-			mask |= hpd_ibx[intel_encoder->hpd_pin];
+			if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
+				mask |= hpd_ibx[intel_encoder->hpd_pin];
 		mask |= SDE_GMBUS | SDE_AUX_MASK;
 	} else {
 		mask &= ~SDE_HOTPLUG_MASK_CPT;
 		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-			mask |= hpd_cpt[intel_encoder->hpd_pin];
+			if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
+				mask |= hpd_cpt[intel_encoder->hpd_pin];
 		mask |= SDE_GMBUS_CPT | SDE_AUX_MASK_CPT;
 	}
 	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
@@ -2514,7 +2548,8 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
+				if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915))
+					i915_hpd_irq_setup(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
@@ -2668,7 +2703,7 @@ static void i915_hpd_irq_setup(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct intel_encoder *encoder;
+	struct intel_encoder *intel_encoder;
 	u32 hotplug_en;
 
 	if (I915_HAS_HOTPLUG(dev)) {
@@ -2677,7 +2712,8 @@ static void i915_hpd_irq_setup(struct drm_device *dev)
 		/* Note HDMI and DP share hotplug bits */
 		/* enable bits are the same for all generations */
 		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-			hotplug_en |= hpd_mask_i915[intel_encoder->hpd_pin];
+			if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
+				hotplug_en |= hpd_mask_i915[intel_encoder->hpd_pin];
 		/* Programming the CRT detection parameters tends
 		   to generate a spurious hotplug event about three
 		   seconds later.  So just do it once.
@@ -2751,8 +2787,9 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger,
-							 IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
+				if (hotplug_irq_storm_detect(dev, hotplug_trigger,
+							    IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965))
+					i915_hpd_irq_setup(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
-- 
1.7.7

[PATCH v.2 10/12] DRM/i915: Add Reenable Timer to turn Hotplug Detection back on.

[Egbert Eich]

We disable hoptplug detection when we encounter a hotplug event
storm. Still hotplug detection is required on some outputs (like
Display Port). The interrupt storm may be only temporary (on certain
Dell Laptops for instance it happens at certain charging states of
the system). Thus we enable it after a certain grace period (2 minutes).
Should the interrupt storm persist it will be detected immediately
and it will be disabled again.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    2 +
 drivers/gpu/drm/i915/i915_irq.c |   53 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 54 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6ca742d..58bee7a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1068,6 +1068,8 @@ typedef struct drm_i915_private {
 			HPD_MARK_DISABLED = 2
 		} hpd_mark;
 	} hpd_stats[HPD_NUM_PINS];
+#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
+	struct timer_list hotplug_reenable_timer;
 } drm_i915_private_t;
 
 /* Iterate over initialised rings */
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 8878fdd..ba598e3 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -376,8 +376,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
 			connector_disabled = true;
 		}
 	}
-	if (connector_disabled)
+	if (connector_disabled) {
 		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
+		mod_timer(&dev_priv->hotplug_reenable_timer,
+			  jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
+	}
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
@@ -2253,6 +2256,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	for_each_pipe(pipe)
 		I915_WRITE(PIPESTAT(pipe), 0xffff);
 
@@ -2274,6 +2279,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	I915_WRITE(HWSTAM, 0xffffffff);
 
 	I915_WRITE(DEIMR, 0xffffffff);
@@ -2612,6 +2619,8 @@ static void i915_irq_uninstall(struct drm_device * dev)
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	if (I915_HAS_HOTPLUG(dev)) {
 		I915_WRITE(PORT_HOTPLUG_EN, 0);
 		I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
@@ -2860,6 +2869,8 @@ static void i965_irq_uninstall(struct drm_device * dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	I915_WRITE(PORT_HOTPLUG_EN, 0);
 	I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
 
@@ -2875,6 +2886,44 @@ static void i965_irq_uninstall(struct drm_device * dev)
 	I915_WRITE(IIR, I915_READ(IIR));
 }
 
+static void i915_reenable_hotplug_timer_func(unsigned long data)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *)data;
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	unsigned long irqflags;
+	int i;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	for (i = 1; i < HPD_NUM_PINS; i++) {
+		if (dev_priv->hpd_stats[i].hpd_mark == HPD_MARK_DISABLED) {
+			struct drm_connector *connector;
+
+			dev_priv->hpd_stats[i].hpd_mark = HPD_ENABLED;
+			list_for_each_entry(connector, &mode_config->connector_list, head) {
+				struct intel_connector *intel_connector = to_intel_connector(connector);
+
+				if (intel_connector->encoder->hpd_pin == i) {
+					if (connector->polled != intel_connector->polled)
+						DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
+							 drm_get_connector_name(connector));
+					connector->polled = intel_connector->polled;
+					if (!connector->polled)
+						connector->polled = DRM_CONNECTOR_POLL_HPD;
+				}
+			}
+
+			if (IS_HASWELL(dev) ||
+			    IS_IVYBRIDGE(dev) ||
+			    (HAS_PCH_SPLIT(dev)))
+				ibx_hpd_irq_setup(dev);
+			else
+				i915_hpd_irq_setup(dev);
+		}
+	}
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
 void intel_irq_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -2887,6 +2936,8 @@ void intel_irq_init(struct drm_device *dev)
 	setup_timer(&dev_priv->gpu_error.hangcheck_timer,
 		    i915_hangcheck_elapsed,
 		    (unsigned long) dev);
+	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
+		    (unsigned long) dev_priv);
 
 	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
 
-- 
1.7.7

[PATCH v.2 11/12] DRM/i915: Add bit field to record which pins have received HPD events.

[Egbert Eich]

This way it is possible to limit 're'-detect() of displays to connectors
which have received an HPD event.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    1 +
 drivers/gpu/drm/i915/i915_irq.c |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 58bee7a..cd6391c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1068,6 +1068,7 @@ typedef struct drm_i915_private {
 			HPD_MARK_DISABLED = 2
 		} hpd_mark;
 	} hpd_stats[HPD_NUM_PINS];
+	u32 hpd_event_bits;
 #define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
 	struct timer_list hotplug_reenable_timer;
 } drm_i915_private_t;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index ba598e3..6e7b0b5 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -353,6 +353,7 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_connector *connector;
 	unsigned long irqflags;
 	bool connector_disabled = false;
+	u32 hpd_event_bits;
 
 	/* HPD irq before everything is fully set up. */
 	if (!dev_priv->enable_hotplug_processing)
@@ -362,6 +363,9 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	hpd_event_bits = dev_priv->hpd_event_bits;
+	dev_priv->hpd_event_bits = 0;
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
 		intel_connector = to_intel_connector(connector);
 		intel_encoder = intel_connector->encoder;
@@ -375,6 +379,10 @@ static void i915_hotplug_work_func(struct work_struct *work)
 				| DRM_CONNECTOR_POLL_DISCONNECT;
 			connector_disabled = true;
 		}
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
+				      drm_get_connector_name(connector), intel_encoder->hpd_pin);
+		}
 	}
 	if (connector_disabled) {
 		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
@@ -629,12 +637,14 @@ static inline bool hotplug_irq_storm_detect(struct drm_device *dev,
 	for (i = 1; i < HPD_NUM_PINS; i++) {
 		if ((hpd[i] & hotplug_trigger) &&
 		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
+			dev_priv->hpd_event_bits |= (1 << i);
 			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
 			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
 				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
 				dev_priv->hpd_stats[i].hpd_cnt = 0;
 			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
 				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
+				dev_priv->hpd_event_bits &= ~(1 << i);
 				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
 				ret = true;
 			} else
-- 
1.7.7

[PATCH v.2 12/12] DRM/i915: Only reprobe display on encoder which has received an HPD event.

[Egbert Eich]

Instead of calling into the DRM helper layer to poll all connectors for
changes in connected displays probe only those connectors which have
received a hotplug event.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   37 +++++++++++++++++++++++++++++++------
 1 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6e7b0b5..6c96d71 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -339,6 +339,24 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
 						     crtc);
 }
 
+/**
+ * drm_helper_hpd_irq_single_connector_event() - call this function with mode_config.mutex lock held
+ */
+
+static int intel_hpd_irq_single_connector_event(struct drm_device *dev, struct drm_connector *connector)
+{
+	enum drm_connector_status old_status;
+
+	old_status = connector->status;
+
+	connector->status = connector->funcs->detect(connector, false);
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
+		      connector->base.id,
+		      drm_get_connector_name(connector),
+		      old_status, connector->status);
+	return (old_status != connector->status);
+}
+
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
@@ -353,6 +371,7 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_connector *connector;
 	unsigned long irqflags;
 	bool connector_disabled = false;
+	bool changed = false;
 	u32 hpd_event_bits;
 
 	/* HPD irq before everything is fully set up. */
@@ -392,14 +411,20 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
-	list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-		if (intel_encoder->hot_plug)
-			intel_encoder->hot_plug(encoder);
-
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		intel_connector = to_intel_connector(connector);
+		intel_encoder = intel_connector->encoder;
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			if (intel_encoder->hot_plug)
+				intel_encoder->hot_plug(intel_encoder);
+			if (intel_hpd_irq_single_connector_event(dev, connector))
+				changed = true;
+		}
+	}
 	mutex_unlock(&mode_config->mutex);
 
-	/* Just fire off a uevent and let userspace tell us what to do */
-	drm_helper_hpd_irq_event(dev);
+	if (changed)
+		drm_kms_helper_hotplug_event(dev);
 }
 
 static void ironlake_handle_rps_change(struct drm_device *dev)
-- 
1.7.7

Re: [PATCH v.2 03/12] DRM/i915: Convert HPD interrupts to make use of HPD pin assignment in encoders.

[Chris Wilson]

On Mon, Feb 25, 2013 at 12:06:50PM -0500, Egbert Eich wrote:
> This allows to enable HPD interrupts for individual pins to only receive
> hotplug events from lines which are connected and working.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_irq.c |  160 ++++++++++++++++++++++++--------------
>  drivers/gpu/drm/i915/i915_reg.h |   32 ++++++++-
>  2 files changed, 132 insertions(+), 60 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 5fd3267..306cd79 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -36,6 +36,68 @@
>  #include "i915_trace.h"
>  #include "intel_drv.h"
>  
> +static const u32 hpd_ibx[] = {
> +	0, /* HPD_NONE */
> +	SDE_CRT_HOTPLUG, /* HPD_CRT */
> +	SDE_SDVOB_HOTPLUG, /* HPD_SDVO_B */
> +	0, /* HPD_SDVO_C */
> +	SDE_PORTB_HOTPLUG, /* HPD_PORT_B */
> +	SDE_PORTC_HOTPLUG, /* HPD_PORT_C */
> +	SDE_PORTD_HOTPLUG  /* HPD_PORT_D */
> +};

Trivial bikeshed, these would look neater as
  static const u32 hpd_ibx[] = {
	[HPD_CRT] = SDE_CRTC_HOTPLUG,
	[HPD_SDVO_B] = SDE_SDVOB_HOTPLUG,
	[HPD_PORT_B] = SDE_PORTB_HOTPLUG,
	[HPD_PORT_C] = SDE_PORTC_HOTPLUG,
	[HPD_PORT_D] = SDE_PORTD_HOTPLUG,
  };
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH v.2 06/12] DRM/i915: Add HPD IRQ storm detection.

[Chris Wilson]

On Mon, Feb 25, 2013 at 12:06:53PM -0500, Egbert Eich wrote:
> Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
> fires more than 5 times / sec).

> Mask out this specific interrupt and revert to polling on the associated
> output.

Hmm, not convinced that just marking it as HPD_MARK_DISABLED does that.
It certainly prevents the irq from sending the uevent, but we have not
yet disabled the irq or enabled drm_kms_helper.poll for this connector.
Though userspace polling is unaffected.

> Rationale:
> Despite of the many attempts to fix the problem with noisy hotplug
> interrupt lines we are still seeing systems which have issues:
> Once cause of noise seems to be bad routing of the hotplug line
> on the board: cross talk from other signals seems to cause erronous
> hotplug interrupts. This has been documented as an erratum for the
> the i945GM chipset and thus hotplug support was disabled for this
> chipset model but others seem to have this problem, too.
> 
> We have seen this issue on a G35 motherboard for example:
> Even different motherboards of the same model seem to behave
> differently: while some only see only around 10-100 interrupts/s
> others seem to see 5k or more.
> We've also observed a dependency on the selected video mode.
> 
> Also on certain laptops interrupt noise seems to occur duing
> battery charging when the battery is at a certain charge levels.
> 
> Thus we add a simple algorithm here that detects an 'interrupt storm'
> condition.

Looks sane.

> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_drv.h |    9 +++++
>  drivers/gpu/drm/i915/i915_irq.c |   63 +++++++++++++++++++++++++++++++-------
>  2 files changed, 60 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index d8604a6..6ca742d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1059,6 +1059,15 @@ typedef struct drm_i915_private {
>  	/* Old dri1 support infrastructure, beware the dragons ya fools entering
>  	 * here! */
>  	struct i915_dri1_state dri1;
> +	struct {
> +		unsigned long hpd_last_jiffies;
> +		int hpd_cnt;
> +		enum {
> +			HPD_ENABLED = 0,
> +			HPD_DISABLED = 1,
> +			HPD_MARK_DISABLED = 2
> +		} hpd_mark;
> +	} hpd_stats[HPD_NUM_PINS];

Please don't put it below dri1 -- as it may then be confused with our
legacy burden.

>  } drm_i915_private_t;
>  
>  /* Iterate over initialised rings */
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index c6ae7ae..08a0934 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -587,6 +587,34 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
>  	queue_work(dev_priv->wq, &dev_priv->rps.work);
>  }
>  
> +static inline void hotplug_irq_storm_detect(struct drm_device *dev,
> +					    u32 hotplug_trigger,
> +					    const u32 *hpd)
> +{
> +	drm_i915_private_t *dev_priv = dev->dev_private;
> +	unsigned long irqflags;
> +	int i;
> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +
> +	for (i = 1; i < HPD_NUM_PINS; i++) {
> +		if ((hpd[i] & hotplug_trigger) &&
> +		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
> +			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
> +			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {

if (time_is_after(dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)))

Though it would be simpler if we just stored the adjusted
hpd_last_jiffies.

> +				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
> +				dev_priv->hpd_stats[i].hpd_cnt = 0;
> +			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
> +				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
> +				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
> +			} else
> +				dev_priv->hpd_stats[i].hpd_cnt++;
> +		}
> +	}
> +
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH v.2 00/12] Detect and deal with Interrupt 'Storms' from noisy Hotplug Lines.

[Chris Wilson]

On Mon, Feb 25, 2013 at 12:06:47PM -0500, Egbert Eich wrote:
> I've reworked my 'hotplug interrupt storm detection'-patches and 
> included most of Daniel's suggestions.
> I've looked into adding EDID caching but since this requires some
> larger scale changes and some changes outside of the Intel driver
> it seemed to be a good idea to propose those changes at a later time.
> 
> Egbert Eich (12):
>   DRM/i915: Remove valleyview_hpd_irq_setup.
>   DRM/I915: Add enum hpd_pin to intel_encoder.
>   DRM/i915: Convert HPD interrupts to make use of HPD pin assignment in
>     encoders.
>   DRM/i915: Remove i965_hpd_irq_setup.
>   DRM/i915: Get rid if the 'hotplug_supported_mask' in struct
>     drm_i915_private.
>   DRM/i915: Add HPD IRQ storm detection.
>   DRM/i915: (re)init HPD interrupt storm statistics.
>   DRM/i915: Treat hpd_irq_setup() for ironake and older generations the
>     same way.
>   DRM/i915: Disable HPD interrupt on pin when irq storm is detected.
>   DRM/i915: Add Reenable Timer to turn Hotplug Detection back on.
>   DRM/i915: Add bit field to record which pins have received HPD
>     events.
>   DRM/i915: Only reprobe display on encoder which has received an HPD
>     event.

I'm happy with this series. It seems to do everything that we need to
enable/disable hpd, and tidies up hotplug detection in the process.

Acked-by: Chris Wilson <chris@chris-wilson.co.uk>

Didn't spot anything wrong in the first pass, but I'd like to let the
details soak in a bit before r-b.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

[PATCH v.2 03/12] DRM/i915: Convert HPD interrupts to make use of HPD pin assignment in encoders (v2)

[Egbert Eich]

This allows to enable HPD interrupts for individual pins to only receive
hotplug events from lines which are connected and working.

v2: Restructured initailization of const arrays following a suggstion
    by Chris Wilson <chris@chris-wilson.co.uk>

Signed-off-by: Egbert Eich <eich@suse.de>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_irq.c |  151 ++++++++++++++++++++++++---------------
 drivers/gpu/drm/i915/i915_reg.h |   32 ++++++++-
 2 files changed, 123 insertions(+), 60 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 5fd3267..7bdc90c 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -36,6 +36,59 @@
 #include "i915_trace.h"
 #include "intel_drv.h"
 
+static const u32 hpd_ibx[] = {
+	[HPD_CRT] = SDE_CRT_HOTPLUG,
+	[HPD_SDVO_B] = SDE_SDVOB_HOTPLUG,
+	[HPD_PORT_B] = SDE_PORTB_HOTPLUG,
+	[HPD_PORT_C] = SDE_PORTC_HOTPLUG,
+	[HPD_PORT_D] = SDE_PORTD_HOTPLUG
+};
+
+static const u32 hpd_cpt[] = {
+	[HPD_CRT] = SDE_CRT_HOTPLUG_CPT,
+	[HPD_PORT_B] = SDE_PORTB_HOTPLUG_CPT,
+	[HPD_PORT_C] = SDE_PORTC_HOTPLUG_CPT,
+	[HPD_PORT_D] = SDE_PORTD_HOTPLUG_CPT
+};
+
+static const u32 hpd_mask_i915[] = {
+	[HPD_CRT] = CRT_HOTPLUG_INT_EN,
+	[HPD_SDVO_B] = SDVOB_HOTPLUG_INT_EN,
+	[HPD_SDVO_C] = SDVOC_HOTPLUG_INT_EN,
+	[HPD_PORT_B] = PORTB_HOTPLUG_INT_EN,
+	[HPD_PORT_C] = PORTC_HOTPLUG_INT_EN,
+	[HPD_PORT_D] = PORTD_HOTPLUG_INT_EN
+};
+
+static const u32 hpd_status_gen4[] = {
+	[HPD_CRT] = CRT_HOTPLUG_INT_STATUS,
+	[HPD_SDVO_B] = SDVOB_HOTPLUG_INT_STATUS_G4X,
+	[HPD_SDVO_C] = SDVOC_HOTPLUG_INT_STATUS_G4X,
+	[HPD_PORT_B] = PORTB_HOTPLUG_INT_STATUS,
+	[HPD_PORT_C] = PORTC_HOTPLUG_INT_STATUS,
+	[HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
+};
+
+static const u32 hpd_status_i965[] = {
+	 [HPD_CRT] = CRT_HOTPLUG_INT_STATUS,
+	 [HPD_SDVO_B] = SDVOB_HOTPLUG_INT_STATUS_I965,
+	 [HPD_SDVO_C] = SDVOC_HOTPLUG_INT_STATUS_I965,
+	 [HPD_PORT_B] = PORTB_HOTPLUG_INT_STATUS,
+	 [HPD_PORT_C] = PORTC_HOTPLUG_INT_STATUS,
+	 [HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
+};
+
+static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
+	[HPD_CRT] = CRT_HOTPLUG_INT_STATUS,
+	[HPD_SDVO_B] = SDVOB_HOTPLUG_INT_STATUS_I915,
+	[HPD_SDVO_C] = SDVOC_HOTPLUG_INT_STATUS_I915,
+	[HPD_PORT_B] = PORTB_HOTPLUG_INT_STATUS,
+	[HPD_PORT_C] = PORTC_HOTPLUG_INT_STATUS,
+	[HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
+};
+
+
+
 /* For display hotplug interrupt */
 static void
 ironlake_enable_display_irq(drm_i915_private_t *dev_priv, u32 mask)
@@ -596,7 +649,7 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 
@@ -1940,17 +1993,21 @@ static void ibx_enable_hotplug(struct drm_device *dev)
 static void ibx_irq_postinstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 mask;
-
-	if (HAS_PCH_IBX(dev))
-		mask = SDE_HOTPLUG_MASK |
-		       SDE_GMBUS |
-		       SDE_AUX_MASK;
-	else
-		mask = SDE_HOTPLUG_MASK_CPT |
-		       SDE_GMBUS_CPT |
-		       SDE_AUX_MASK_CPT;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct intel_encoder *intel_encoder;
+	u32 mask = I915_READ(SDEIER);
 
+	if (HAS_PCH_IBX(dev)) {
+		mask &= ~SDE_HOTPLUG_MASK;
+		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
+			mask |= hpd_ibx[intel_encoder->hpd_pin];
+		mask |= SDE_GMBUS | SDE_AUX_MASK;
+	} else {
+		mask &= ~SDE_HOTPLUG_MASK_CPT;
+		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
+			mask |= hpd_cpt[intel_encoder->hpd_pin];
+		mask |= SDE_GMBUS_CPT | SDE_AUX_MASK_CPT;
+	}
 	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
 	I915_WRITE(SDEIMR, ~mask);
 	I915_WRITE(SDEIER, mask);
@@ -2360,26 +2417,16 @@ static int i915_irq_postinstall(struct drm_device *dev)
 
 static void i915_hpd_irq_setup(struct drm_device *dev)
 {
-	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 hotplug_en;
-
 	if (I915_HAS_HOTPLUG(dev)) {
-		hotplug_en = I915_READ(PORT_HOTPLUG_EN);
+		drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+		struct drm_mode_config *mode_config = &dev->mode_config;
+		struct intel_encoder *encoder;
+		u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
 
-		if (dev_priv->hotplug_supported_mask & PORTB_HOTPLUG_INT_STATUS)
-			hotplug_en |= PORTB_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & PORTC_HOTPLUG_INT_STATUS)
-			hotplug_en |= PORTC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & PORTD_HOTPLUG_INT_STATUS)
-			hotplug_en |= PORTD_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-			hotplug_en |= CRT_HOTPLUG_INT_EN;
-			hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-		}
+		hotplug_en &= ~HOTPLUG_INT_EN_MASK;
+		list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
+			hotplug_en |= hpd_mask_i915[encoder->hpd_pin];
+		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
 
 		/* Ignore TV since it's buggy */
 
@@ -2443,7 +2490,7 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 
@@ -2596,38 +2643,22 @@ static int i965_irq_postinstall(struct drm_device *dev)
 static void i965_hpd_irq_setup(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct intel_encoder *encoder;
 	u32 hotplug_en;
 
 	/* Note HDMI and DP share hotplug bits */
 	hotplug_en = 0;
-	if (dev_priv->hotplug_supported_mask & PORTB_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTB_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & PORTC_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTC_HOTPLUG_INT_EN;
-	if (dev_priv->hotplug_supported_mask & PORTD_HOTPLUG_INT_STATUS)
-		hotplug_en |= PORTD_HOTPLUG_INT_EN;
-	if (IS_G4X(dev)) {
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_G4X)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_G4X)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	} else {
-		if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I965)
-			hotplug_en |= SDVOC_HOTPLUG_INT_EN;
-		if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I965)
-			hotplug_en |= SDVOB_HOTPLUG_INT_EN;
-	}
-	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
-		hotplug_en |= CRT_HOTPLUG_INT_EN;
-
-		/* Programming the CRT detection parameters tends
-		   to generate a spurious hotplug event about three
-		   seconds later.  So just do it once.
-		   */
-		if (IS_G4X(dev))
-			hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
-		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
-	}
+	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
+		/* enable bits are the same for all generations */
+		hotplug_en |= hpd_mask_i915[encoder->hpd_pin];
+	/* Programming the CRT detection parameters tends
+	   to generate a spurious hotplug event about three
+	   seconds later.  So just do it once.
+	*/
+	if (IS_G4X(dev))
+		hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
+	hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
 
 	/* Ignore TV since it's buggy */
 
@@ -2690,7 +2721,9 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & dev_priv->hotplug_supported_mask)
+			if (hotplug_status & (IS_G4X(dev) ?
+					      HOTPLUG_INT_STATUS_G4X :
+					      HOTPLUG_INT_STATUS_I965))
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 527b664..c3d2c01 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1637,6 +1637,12 @@
 #define   SDVOC_HOTPLUG_INT_EN			(1 << 25)
 #define   TV_HOTPLUG_INT_EN			(1 << 18)
 #define   CRT_HOTPLUG_INT_EN			(1 << 9)
+#define HOTPLUG_INT_EN_MASK			(PORTB_HOTPLUG_INT_EN | \
+						 PORTC_HOTPLUG_INT_EN | \
+						 PORTD_HOTPLUG_INT_EN | \
+						 SDVOC_HOTPLUG_INT_EN | \
+						 SDVOB_HOTPLUG_INT_EN | \
+						 CRT_HOTPLUG_INT_EN)
 #define   CRT_HOTPLUG_FORCE_DETECT		(1 << 3)
 #define CRT_HOTPLUG_ACTIVATION_PERIOD_32	(0 << 8)
 /* must use period 64 on GM45 according to docs */
@@ -1675,6 +1681,26 @@
 #define   SDVOB_HOTPLUG_INT_STATUS_I965		(3 << 2)
 #define   SDVOC_HOTPLUG_INT_STATUS_I915		(1 << 7)
 #define   SDVOB_HOTPLUG_INT_STATUS_I915		(1 << 6)
+#define   HOTPLUG_INT_STATUS_G4X		(CRT_HOTPLUG_INT_STATUS | \
+						 SDVOB_HOTPLUG_INT_STATUS_G4X | \
+						 SDVOC_HOTPLUG_INT_STATUS_G4X | \
+						 PORTB_HOTPLUG_INT_STATUS | \
+						 PORTC_HOTPLUG_INT_STATUS | \
+						 PORTD_HOTPLUG_INT_STATUS)
+
+#define HOTPLUG_INT_STATUS_I965			(CRT_HOTPLUG_INT_STATUS | \
+						 SDVOB_HOTPLUG_INT_STATUS_I965 | \
+						 SDVOC_HOTPLUG_INT_STATUS_I965 | \
+						 PORTB_HOTPLUG_INT_STATUS | \
+						 PORTC_HOTPLUG_INT_STATUS | \
+						 PORTD_HOTPLUG_INT_STATUS)
+
+#define HOTPLUG_INT_STATUS_I915			(CRT_HOTPLUG_INT_STATUS | \
+						 SDVOB_HOTPLUG_INT_STATUS_I915 | \
+						 SDVOC_HOTPLUG_INT_STATUS_I915 | \
+						 PORTB_HOTPLUG_INT_STATUS | \
+						 PORTC_HOTPLUG_INT_STATUS | \
+						 PORTD_HOTPLUG_INT_STATUS)
 
 /* SDVO port control */
 #define SDVOB			0x61140
@@ -3508,7 +3534,11 @@
 #define SDE_PORTC_HOTPLUG       (1 << 9)
 #define SDE_PORTB_HOTPLUG       (1 << 8)
 #define SDE_SDVOB_HOTPLUG       (1 << 6)
-#define SDE_HOTPLUG_MASK	(0xf << 8)
+#define SDE_HOTPLUG_MASK        (SDE_CRT_HOTPLUG | \
+				 SDE_SDVOB_HOTPLUG |	\
+				 SDE_PORTB_HOTPLUG |	\
+				 SDE_PORTC_HOTPLUG |	\
+				 SDE_PORTD_HOTPLUG)
 #define SDE_TRANSB_CRC_DONE	(1 << 5)
 #define SDE_TRANSB_CRC_ERR	(1 << 4)
 #define SDE_TRANSB_FIFO_UNDER	(1 << 3)
-- 
1.7.7

[PATCH v.2 06/12] DRM/i915: Add HPD IRQ storm detection (v2)

[Egbert Eich]

Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
fires more than 5 times / sec).
Rationale:
Despite of the many attempts to fix the problem with noisy hotplug
interrupt lines we are still seeing systems which have issues:
Once cause of noise seems to be bad routing of the hotplug line
on the board: cross talk from other signals seems to cause erronous
hotplug interrupts. This has been documented as an erratum for the
the i945GM chipset and thus hotplug support was disabled for this
chipset model but others seem to have this problem, too.

We have seen this issue on a G35 motherboard for example:
Even different motherboards of the same model seem to behave
differently: while some only see only around 10-100 interrupts/s
others seem to see 5k or more.
We've also observed a dependency on the selected video mode.

Also on certain laptops interrupt noise seems to occur duing
battery charging when the battery is at a certain charge levels.

Thus we add a simple algorithm here that detects an 'interrupt storm'
condition.

v2: Fixed comment.

Signed-off-by: Egbert Eich <eich@suse.de>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_drv.h |    9 +++++
 drivers/gpu/drm/i915/i915_irq.c |   63 +++++++++++++++++++++++++++++++-------
 2 files changed, 60 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d8604a6..6ca742d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1059,6 +1059,15 @@ typedef struct drm_i915_private {
 	/* Old dri1 support infrastructure, beware the dragons ya fools entering
 	 * here! */
 	struct i915_dri1_state dri1;
+	struct {
+		unsigned long hpd_last_jiffies;
+		int hpd_cnt;
+		enum {
+			HPD_ENABLED = 0,
+			HPD_DISABLED = 1,
+			HPD_MARK_DISABLED = 2
+		} hpd_mark;
+	} hpd_stats[HPD_NUM_PINS];
 } drm_i915_private_t;
 
 /* Iterate over initialised rings */
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index c40c7cc..24cb6ed 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -578,6 +578,34 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
 	queue_work(dev_priv->wq, &dev_priv->rps.work);
 }
 
+static inline void hotplug_irq_storm_detect(struct drm_device *dev,
+					    u32 hotplug_trigger,
+					    const u32 *hpd)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	unsigned long irqflags;
+	int i;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	for (i = 1; i < HPD_NUM_PINS; i++) {
+		if ((hpd[i] & hotplug_trigger) &&
+		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
+			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
+			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
+				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
+				dev_priv->hpd_stats[i].hpd_cnt = 0;
+			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
+				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
+				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
+			} else
+				dev_priv->hpd_stats[i].hpd_cnt++;
+		}
+	}
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
 static void gmbus_irq_handler(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -646,13 +674,15 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
-			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
@@ -676,10 +706,12 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
 
-	if (pch_iir & SDE_HOTPLUG_MASK)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK) >>
@@ -722,10 +754,12 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
 
-	if (pch_iir & SDE_HOTPLUG_MASK_CPT)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
@@ -2468,13 +2502,15 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 		if ((I915_HAS_HOTPLUG(dev)) &&
 		    (iir & I915_DISPLAY_PORT_INTERRUPT)) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			POSTING_READ(PORT_HOTPLUG_STAT);
 		}
@@ -2701,15 +2737,18 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & (IS_G4X(dev) ?
+								  HOTPLUG_INT_STATUS_G4X :
+								  HOTPLUG_INT_STATUS_I965);
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & (IS_G4X(dev) ?
-					      HOTPLUG_INT_STATUS_G4X :
-					      HOTPLUG_INT_STATUS_I965))
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger,
+							 IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
-- 
1.7.7

Re: [PATCH v.2 06/12] DRM/i915: Add HPD IRQ storm detection (v2)

[Daniel Vetter]

On Thu, Feb 28, 2013 at 04:19:15AM -0500, Egbert Eich wrote:
> Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
> fires more than 5 times / sec).
> Rationale:
> Despite of the many attempts to fix the problem with noisy hotplug
> interrupt lines we are still seeing systems which have issues:
> Once cause of noise seems to be bad routing of the hotplug line
> on the board: cross talk from other signals seems to cause erronous
> hotplug interrupts. This has been documented as an erratum for the
> the i945GM chipset and thus hotplug support was disabled for this
> chipset model but others seem to have this problem, too.
> 
> We have seen this issue on a G35 motherboard for example:
> Even different motherboards of the same model seem to behave
> differently: while some only see only around 10-100 interrupts/s
> others seem to see 5k or more.
> We've also observed a dependency on the selected video mode.
> 
> Also on certain laptops interrupt noise seems to occur duing
> battery charging when the battery is at a certain charge levels.
> 
> Thus we add a simple algorithm here that detects an 'interrupt storm'
> condition.
> 
> v2: Fixed comment.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_drv.h |    9 +++++
>  drivers/gpu/drm/i915/i915_irq.c |   63 +++++++++++++++++++++++++++++++-------
>  2 files changed, 60 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index d8604a6..6ca742d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1059,6 +1059,15 @@ typedef struct drm_i915_private {
>  	/* Old dri1 support infrastructure, beware the dragons ya fools entering
>  	 * here! */
>  	struct i915_dri1_state dri1;
> +	struct {
> +		unsigned long hpd_last_jiffies;
> +		int hpd_cnt;
> +		enum {
> +			HPD_ENABLED = 0,
> +			HPD_DISABLED = 1,
> +			HPD_MARK_DISABLED = 2
> +		} hpd_mark;
> +	} hpd_stats[HPD_NUM_PINS];

It's still hidden in the dri1 dungeon ;-) Imo this would fit nicely next
to the existing hotplug work and state tracking stuff.
-Daniel

>  } drm_i915_private_t;
>  
>  /* Iterate over initialised rings */
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index c40c7cc..24cb6ed 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -578,6 +578,34 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
>  	queue_work(dev_priv->wq, &dev_priv->rps.work);
>  }
>  
> +static inline void hotplug_irq_storm_detect(struct drm_device *dev,
> +					    u32 hotplug_trigger,
> +					    const u32 *hpd)
> +{
> +	drm_i915_private_t *dev_priv = dev->dev_private;
> +	unsigned long irqflags;
> +	int i;
> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +
> +	for (i = 1; i < HPD_NUM_PINS; i++) {
> +		if ((hpd[i] & hotplug_trigger) &&
> +		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
> +			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
> +			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
> +				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
> +				dev_priv->hpd_stats[i].hpd_cnt = 0;
> +			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
> +				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
> +				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
> +			} else
> +				dev_priv->hpd_stats[i].hpd_cnt++;
> +		}
> +	}
> +
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> +
>  static void gmbus_irq_handler(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private;
> @@ -646,13 +674,15 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
>  		/* Consume port.  Then clear IIR or we'll miss events */
>  		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
>  			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
> +			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
>  
>  			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
>  					 hotplug_status);
> -			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
> +			if (hotplug_trigger) {
> +				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
>  				queue_work(dev_priv->wq,
>  					   &dev_priv->hotplug_work);
> -
> +			}
>  			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
>  			I915_READ(PORT_HOTPLUG_STAT);
>  		}
> @@ -676,10 +706,12 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
>  {
>  	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
>  	int pipe;
> +	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
>  
> -	if (pch_iir & SDE_HOTPLUG_MASK)
> +	if (hotplug_trigger) {
> +		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
>  		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
> -
> +	}
>  	if (pch_iir & SDE_AUDIO_POWER_MASK)
>  		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
>  				 (pch_iir & SDE_AUDIO_POWER_MASK) >>
> @@ -722,10 +754,12 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
>  {
>  	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
>  	int pipe;
> +	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
>  
> -	if (pch_iir & SDE_HOTPLUG_MASK_CPT)
> +	if (hotplug_trigger) {
> +		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
>  		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
> -
> +	}
>  	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
>  		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
>  				 (pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
> @@ -2468,13 +2502,15 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
>  		if ((I915_HAS_HOTPLUG(dev)) &&
>  		    (iir & I915_DISPLAY_PORT_INTERRUPT)) {
>  			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
> +			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
>  
>  			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
>  				  hotplug_status);
> -			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
> +			if (hotplug_trigger) {
> +				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
>  				queue_work(dev_priv->wq,
>  					   &dev_priv->hotplug_work);
> -
> +			}
>  			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
>  			POSTING_READ(PORT_HOTPLUG_STAT);
>  		}
> @@ -2701,15 +2737,18 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
>  		/* Consume port.  Then clear IIR or we'll miss events */
>  		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
>  			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
> +			u32 hotplug_trigger = hotplug_status & (IS_G4X(dev) ?
> +								  HOTPLUG_INT_STATUS_G4X :
> +								  HOTPLUG_INT_STATUS_I965);
>  
>  			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
>  				  hotplug_status);
> -			if (hotplug_status & (IS_G4X(dev) ?
> -					      HOTPLUG_INT_STATUS_G4X :
> -					      HOTPLUG_INT_STATUS_I965))
> +			if (hotplug_trigger) {
> +				hotplug_irq_storm_detect(dev, hotplug_trigger,
> +							 IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
>  				queue_work(dev_priv->wq,
>  					   &dev_priv->hotplug_work);
> -
> +			}
>  			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
>  			I915_READ(PORT_HOTPLUG_STAT);
>  		}
> -- 
> 1.7.7
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

[PATCH v.3 06/12] DRM/i915: Add HPD IRQ storm detection (v3)

[Egbert Eich]

Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
fires more than 5 times / sec).
Rationale:
Despite of the many attempts to fix the problem with noisy hotplug
interrupt lines we are still seeing systems which have issues:
Once cause of noise seems to be bad routing of the hotplug line
on the board: cross talk from other signals seems to cause erronous
hotplug interrupts. This has been documented as an erratum for the
the i945GM chipset and thus hotplug support was disabled for this
chipset model but others seem to have this problem, too.

We have seen this issue on a G35 motherboard for example:
Even different motherboards of the same model seem to behave
differently: while some only see only around 10-100 interrupts/s
others seem to see 5k or more.
We've also observed a dependency on the selected video mode.

Also on certain laptops interrupt noise seems to occur duing
battery charging when the battery is at a certain charge levels.

Thus we add a simple algorithm here that detects an 'interrupt storm'
condition.

v2: Fixed comment.
v3: Reordered drm_i915_private: moved hpd state tracking to hotplug work stuff.

Signed-off-by: Egbert Eich <eich@suse.de>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_drv.h |    9 +++++
 drivers/gpu/drm/i915/i915_irq.c |   63 +++++++++++++++++++++++++++++++-------
 2 files changed, 60 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d8604a6..296278f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -924,6 +924,15 @@ typedef struct drm_i915_private {
 
 	struct work_struct hotplug_work;
 	bool enable_hotplug_processing;
+	struct {
+		unsigned long hpd_last_jiffies;
+		int hpd_cnt;
+		enum {
+			HPD_ENABLED = 0,
+			HPD_DISABLED = 1,
+			HPD_MARK_DISABLED = 2
+		} hpd_mark;
+	} hpd_stats[HPD_NUM_PINS];
 
 	int num_pipe;
 	int num_pch_pll;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index c40c7cc..24cb6ed 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -578,6 +578,34 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
 	queue_work(dev_priv->wq, &dev_priv->rps.work);
 }
 
+static inline void hotplug_irq_storm_detect(struct drm_device *dev,
+					    u32 hotplug_trigger,
+					    const u32 *hpd)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	unsigned long irqflags;
+	int i;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	for (i = 1; i < HPD_NUM_PINS; i++) {
+		if ((hpd[i] & hotplug_trigger) &&
+		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
+			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
+			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
+				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
+				dev_priv->hpd_stats[i].hpd_cnt = 0;
+			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
+				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
+				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
+			} else
+				dev_priv->hpd_stats[i].hpd_cnt++;
+		}
+	}
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
 static void gmbus_irq_handler(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private;
@@ -646,13 +674,15 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
-			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
@@ -676,10 +706,12 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
 
-	if (pch_iir & SDE_HOTPLUG_MASK)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK) >>
@@ -722,10 +754,12 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
+	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
 
-	if (pch_iir & SDE_HOTPLUG_MASK_CPT)
+	if (hotplug_trigger) {
+		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
-
+	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
 		DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
 				 (pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
@@ -2468,13 +2502,15 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 		if ((I915_HAS_HOTPLUG(dev)) &&
 		    (iir & I915_DISPLAY_PORT_INTERRUPT)) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & HOTPLUG_INT_STATUS_I915)
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			POSTING_READ(PORT_HOTPLUG_STAT);
 		}
@@ -2701,15 +2737,18 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 		/* Consume port.  Then clear IIR or we'll miss events */
 		if (iir & I915_DISPLAY_PORT_INTERRUPT) {
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
+			u32 hotplug_trigger = hotplug_status & (IS_G4X(dev) ?
+								  HOTPLUG_INT_STATUS_G4X :
+								  HOTPLUG_INT_STATUS_I965);
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
-			if (hotplug_status & (IS_G4X(dev) ?
-					      HOTPLUG_INT_STATUS_G4X :
-					      HOTPLUG_INT_STATUS_I965))
+			if (hotplug_trigger) {
+				hotplug_irq_storm_detect(dev, hotplug_trigger,
+							 IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
-
+			}
 			I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
 			I915_READ(PORT_HOTPLUG_STAT);
 		}
-- 
1.7.7

[PATCH v.2 10/12] DRM/i915: Add Reenable Timer to turn Hotplug Detection back on (v2).

[Egbert Eich]

We disable hoptplug detection when we encounter a hotplug event
storm. Still hotplug detection is required on some outputs (like
Display Port). The interrupt storm may be only temporary (on certain
Dell Laptops for instance it happens at certain charging states of
the system). Thus we enable it after a certain grace period (2 minutes).
Should the interrupt storm persist it will be detected immediately
and it will be disabled again.

v2: Reordered drm_i915_private: moved hotplug_reenable_timer to hpd state tracker.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    2 +
 drivers/gpu/drm/i915/i915_irq.c |   53 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 54 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 296278f..1fb7c44 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -933,6 +933,8 @@ typedef struct drm_i915_private {
 			HPD_MARK_DISABLED = 2
 		} hpd_mark;
 	} hpd_stats[HPD_NUM_PINS];
+#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
+	struct timer_list hotplug_reenable_timer;
 
 	int num_pipe;
 	int num_pch_pll;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d11534c..c688b27 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -367,8 +367,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
 			connector_disabled = true;
 		}
 	}
-	if (connector_disabled)
+	if (connector_disabled) {
 		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
+		mod_timer(&dev_priv->hotplug_reenable_timer,
+			  jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
+	}
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
@@ -2244,6 +2247,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	for_each_pipe(pipe)
 		I915_WRITE(PIPESTAT(pipe), 0xffff);
 
@@ -2265,6 +2270,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	I915_WRITE(HWSTAM, 0xffffffff);
 
 	I915_WRITE(DEIMR, 0xffffffff);
@@ -2603,6 +2610,8 @@ static void i915_irq_uninstall(struct drm_device * dev)
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	if (I915_HAS_HOTPLUG(dev)) {
 		I915_WRITE(PORT_HOTPLUG_EN, 0);
 		I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
@@ -2851,6 +2860,8 @@ static void i965_irq_uninstall(struct drm_device * dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	I915_WRITE(PORT_HOTPLUG_EN, 0);
 	I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
 
@@ -2866,6 +2877,44 @@ static void i965_irq_uninstall(struct drm_device * dev)
 	I915_WRITE(IIR, I915_READ(IIR));
 }
 
+static void i915_reenable_hotplug_timer_func(unsigned long data)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *)data;
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	unsigned long irqflags;
+	int i;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	for (i = 1; i < HPD_NUM_PINS; i++) {
+		if (dev_priv->hpd_stats[i].hpd_mark == HPD_MARK_DISABLED) {
+			struct drm_connector *connector;
+
+			dev_priv->hpd_stats[i].hpd_mark = HPD_ENABLED;
+			list_for_each_entry(connector, &mode_config->connector_list, head) {
+				struct intel_connector *intel_connector = to_intel_connector(connector);
+
+				if (intel_connector->encoder->hpd_pin == i) {
+					if (connector->polled != intel_connector->polled)
+						DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
+							 drm_get_connector_name(connector));
+					connector->polled = intel_connector->polled;
+					if (!connector->polled)
+						connector->polled = DRM_CONNECTOR_POLL_HPD;
+				}
+			}
+
+			if (IS_HASWELL(dev) ||
+			    IS_IVYBRIDGE(dev) ||
+			    (HAS_PCH_SPLIT(dev)))
+				ibx_hpd_irq_setup(dev);
+			else
+				i915_hpd_irq_setup(dev);
+		}
+	}
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
 void intel_irq_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -2878,6 +2927,8 @@ void intel_irq_init(struct drm_device *dev)
 	setup_timer(&dev_priv->gpu_error.hangcheck_timer,
 		    i915_hangcheck_elapsed,
 		    (unsigned long) dev);
+	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
+		    (unsigned long) dev_priv);
 
 	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
 
-- 
1.7.7

[PATCH v.2 11/12] DRM/i915: Add bit field to record which pins have received HPD events (v2)

[Egbert Eich]

This way it is possible to limit 're'-detect() of displays to connectors
which have received an HPD event.

v2: Reordered drm_i915_private: Move hpd_event_bits to hpd state tracking.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    1 +
 drivers/gpu/drm/i915/i915_irq.c |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1fb7c44..d48d1e6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -933,6 +933,7 @@ typedef struct drm_i915_private {
 			HPD_MARK_DISABLED = 2
 		} hpd_mark;
 	} hpd_stats[HPD_NUM_PINS];
+	u32 hpd_event_bits;
 #define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
 	struct timer_list hotplug_reenable_timer;
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index c688b27..223813f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -344,6 +344,7 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_connector *connector;
 	unsigned long irqflags;
 	bool connector_disabled = false;
+	u32 hpd_event_bits;
 
 	/* HPD irq before everything is fully set up. */
 	if (!dev_priv->enable_hotplug_processing)
@@ -353,6 +354,9 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	hpd_event_bits = dev_priv->hpd_event_bits;
+	dev_priv->hpd_event_bits = 0;
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
 		intel_connector = to_intel_connector(connector);
 		intel_encoder = intel_connector->encoder;
@@ -366,6 +370,10 @@ static void i915_hotplug_work_func(struct work_struct *work)
 				| DRM_CONNECTOR_POLL_DISCONNECT;
 			connector_disabled = true;
 		}
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
+				      drm_get_connector_name(connector), intel_encoder->hpd_pin);
+		}
 	}
 	if (connector_disabled) {
 		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
@@ -620,12 +628,14 @@ static inline bool hotplug_irq_storm_detect(struct drm_device *dev,
 	for (i = 1; i < HPD_NUM_PINS; i++) {
 		if ((hpd[i] & hotplug_trigger) &&
 		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
+			dev_priv->hpd_event_bits |= (1 << i);
 			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
 			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
 				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
 				dev_priv->hpd_stats[i].hpd_cnt = 0;
 			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
 				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
+				dev_priv->hpd_event_bits &= ~(1 << i);
 				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
 				ret = true;
 			} else
-- 
1.7.7

Re: [PATCH v.2 10/12] DRM/i915: Add Reenable Timer to turn Hotplug Detection back on (v2).

[Ville Syrjälä]

On Tue, Mar 05, 2013 at 02:48:49AM -0500, Egbert Eich wrote:
> We disable hoptplug detection when we encounter a hotplug event
> storm. Still hotplug detection is required on some outputs (like
> Display Port). The interrupt storm may be only temporary (on certain
> Dell Laptops for instance it happens at certain charging states of
> the system). Thus we enable it after a certain grace period (2 minutes).
> Should the interrupt storm persist it will be detected immediately
> and it will be disabled again.
> 
> v2: Reordered drm_i915_private: moved hotplug_reenable_timer to hpd state tracker.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_drv.h |    2 +
>  drivers/gpu/drm/i915/i915_irq.c |   53 ++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 54 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 296278f..1fb7c44 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -933,6 +933,8 @@ typedef struct drm_i915_private {
>  			HPD_MARK_DISABLED = 2
>  		} hpd_mark;
>  	} hpd_stats[HPD_NUM_PINS];
> +#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
> +	struct timer_list hotplug_reenable_timer;
>  
>  	int num_pipe;
>  	int num_pch_pll;
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index d11534c..c688b27 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -367,8 +367,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
>  			connector_disabled = true;
>  		}
>  	}
> -	if (connector_disabled)
> +	if (connector_disabled) {
>  		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
> +		mod_timer(&dev_priv->hotplug_reenable_timer,
> +			  jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
> +	}
>  
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
>  
> @@ -2244,6 +2247,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	for_each_pipe(pipe)
>  		I915_WRITE(PIPESTAT(pipe), 0xffff);
>  
> @@ -2265,6 +2270,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	I915_WRITE(HWSTAM, 0xffffffff);
>  
>  	I915_WRITE(DEIMR, 0xffffffff);
> @@ -2603,6 +2610,8 @@ static void i915_irq_uninstall(struct drm_device * dev)
>  	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
>  	int pipe;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	if (I915_HAS_HOTPLUG(dev)) {
>  		I915_WRITE(PORT_HOTPLUG_EN, 0);
>  		I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
> @@ -2851,6 +2860,8 @@ static void i965_irq_uninstall(struct drm_device * dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	I915_WRITE(PORT_HOTPLUG_EN, 0);
>  	I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
>  
> @@ -2866,6 +2877,44 @@ static void i965_irq_uninstall(struct drm_device * dev)
>  	I915_WRITE(IIR, I915_READ(IIR));
>  }
>  
> +static void i915_reenable_hotplug_timer_func(unsigned long data)
> +{
> +	drm_i915_private_t *dev_priv = (drm_i915_private_t *)data;
> +	struct drm_device *dev = dev_priv->dev;
> +	struct drm_mode_config *mode_config = &dev->mode_config;
> +	unsigned long irqflags;
> +	int i;
> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +	for (i = 1; i < HPD_NUM_PINS; i++) {

Maybe include a small comment to avoid people thinking the 'i = 1' is
a typo.

> +		if (dev_priv->hpd_stats[i].hpd_mark == HPD_MARK_DISABLED) {

This is getting quite deep. This could help a bit:

if (dev_priv->hpd_stats[i].hpd_mark != HPD_MARK_DISABLED)
	continue;

> +			struct drm_connector *connector;
> +
> +			dev_priv->hpd_stats[i].hpd_mark = HPD_ENABLED;
> +			list_for_each_entry(connector, &mode_config->connector_list, head) {
> +				struct intel_connector *intel_connector = to_intel_connector(connector);
> +
> +				if (intel_connector->encoder->hpd_pin == i) {
> +					if (connector->polled != intel_connector->polled)
> +						DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
> +							 drm_get_connector_name(connector));
> +					connector->polled = intel_connector->polled;
> +					if (!connector->polled)
> +						connector->polled = DRM_CONNECTOR_POLL_HPD;
> +				}
> +			}
> +
> +			if (IS_HASWELL(dev) ||
> +			    IS_IVYBRIDGE(dev) ||
> +			    (HAS_PCH_SPLIT(dev)))

IS_HASWELL() and IS_IVYBRIDGE() are superfluous.

> +				ibx_hpd_irq_setup(dev);
> +			else
> +				i915_hpd_irq_setup(dev);
> +		}
> +	}
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> +
>  void intel_irq_init(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -2878,6 +2927,8 @@ void intel_irq_init(struct drm_device *dev)
>  	setup_timer(&dev_priv->gpu_error.hangcheck_timer,
>  		    i915_hangcheck_elapsed,
>  		    (unsigned long) dev);
> +	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
> +		    (unsigned long) dev_priv);
>  
>  	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
>  
> -- 
> 1.7.7
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC

[PATCH v.3 10/12] DRM/i915: Add Reenable Timer to turn Hotplug Detection back on (v3).

[Egbert Eich]

We disable hoptplug detection when we encounter a hotplug event
storm. Still hotplug detection is required on some outputs (like
Display Port). The interrupt storm may be only temporary (on certain
Dell Laptops for instance it happens at certain charging states of
the system). Thus we enable it after a certain grace period (2 minutes).
Should the interrupt storm persist it will be detected immediately
and it will be disabled again.

v2: Reordered drm_i915_private: moved hotplug_reenable_timer to hpd state tracker.
v3: Clarified loop start value,
    Removed superfluous test for Ivybridge and Haswell,
    Restructured loop to avoid deep nesting (all suggested by Ville Syrjälä)

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    2 +
 drivers/gpu/drm/i915/i915_irq.c |   53 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 54 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 296278f..1fb7c44 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -933,6 +933,8 @@ typedef struct drm_i915_private {
 			HPD_MARK_DISABLED = 2
 		} hpd_mark;
 	} hpd_stats[HPD_NUM_PINS];
+#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
+	struct timer_list hotplug_reenable_timer;
 
 	int num_pipe;
 	int num_pch_pll;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d11534c..76903af 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -367,8 +367,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
 			connector_disabled = true;
 		}
 	}
-	if (connector_disabled)
+	if (connector_disabled) {
 		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
+		mod_timer(&dev_priv->hotplug_reenable_timer,
+			  jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
+	}
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
@@ -2244,6 +2247,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	for_each_pipe(pipe)
 		I915_WRITE(PIPESTAT(pipe), 0xffff);
 
@@ -2265,6 +2270,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	I915_WRITE(HWSTAM, 0xffffffff);
 
 	I915_WRITE(DEIMR, 0xffffffff);
@@ -2603,6 +2610,8 @@ static void i915_irq_uninstall(struct drm_device * dev)
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int pipe;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	if (I915_HAS_HOTPLUG(dev)) {
 		I915_WRITE(PORT_HOTPLUG_EN, 0);
 		I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
@@ -2851,6 +2860,8 @@ static void i965_irq_uninstall(struct drm_device * dev)
 	if (!dev_priv)
 		return;
 
+	del_timer_sync(&dev_priv->hotplug_reenable_timer);
+
 	I915_WRITE(PORT_HOTPLUG_EN, 0);
 	I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
 
@@ -2866,6 +2877,44 @@ static void i965_irq_uninstall(struct drm_device * dev)
 	I915_WRITE(IIR, I915_READ(IIR));
 }
 
+static void i915_reenable_hotplug_timer_func(unsigned long data)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *)data;
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	unsigned long irqflags;
+	int i;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	for (i = (HPD_NONE + 1); i < HPD_NUM_PINS; i++) {
+		struct drm_connector *connector;
+
+		if (dev_priv->hpd_stats[i].hpd_mark != HPD_MARK_DISABLED)
+			continue;
+
+		dev_priv->hpd_stats[i].hpd_mark = HPD_ENABLED;
+
+		list_for_each_entry(connector, &mode_config->connector_list, head) {
+			struct intel_connector *intel_connector = to_intel_connector(connector);
+
+			if (intel_connector->encoder->hpd_pin == i) {
+				if (connector->polled != intel_connector->polled)
+					DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
+							 drm_get_connector_name(connector));
+				connector->polled = intel_connector->polled;
+				if (!connector->polled)
+					connector->polled = DRM_CONNECTOR_POLL_HPD;
+			}
+		}
+
+		if (HAS_PCH_SPLIT(dev))
+			ibx_hpd_irq_setup(dev);
+		else
+			i915_hpd_irq_setup(dev);
+	}
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
 void intel_irq_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -2878,6 +2927,8 @@ void intel_irq_init(struct drm_device *dev)
 	setup_timer(&dev_priv->gpu_error.hangcheck_timer,
 		    i915_hangcheck_elapsed,
 		    (unsigned long) dev);
+	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
+		    (unsigned long) dev_priv);
 
 	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
 
-- 
1.7.7

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx

[PATCH v.2 09/12] DRM/i915: Disable HPD interrupt on pin when irq storm is detected (v2)

[Egbert Eich]

This patch disables hotplug interrupts if an 'interrupt storm'
has been detected.
Noise on the interrupt line renders the hotplug interrupt useless:
each hotplug event causes the devices to be rescanned which will
will only increase the system load.
Thus disable the hotplug interrupts and fall back to periodic
device polling.

v2: Fixed cleanup typo.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   69 ++++++++++++++++++++++++++++++---------
 1 files changed, 53 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d9c99d7..0abef6a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -87,7 +87,8 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 	[HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
 };
 
-
+static void ibx_hpd_irq_setup(struct drm_device *dev);
+static void i915_hpd_irq_setup(struct drm_device *dev);
 
 /* For display hotplug interrupt */
 static void
@@ -338,7 +339,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
 						    hotplug_work);
 	struct drm_device *dev = dev_priv->dev;
 	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct intel_encoder *encoder;
+	struct intel_connector *intel_connector;
+	struct intel_encoder *intel_encoder;
+	struct drm_connector *connector;
+	unsigned long irqflags;
+	bool connector_disabled = false;
 
 	/* HPD irq before everything is fully set up. */
 	if (!dev_priv->enable_hotplug_processing)
@@ -347,9 +352,29 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	mutex_lock(&mode_config->mutex);
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
-	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
-		if (encoder->hot_plug)
-			encoder->hot_plug(encoder);
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		intel_connector = to_intel_connector(connector);
+		intel_encoder = intel_connector->encoder;
+		if (intel_encoder->hpd_pin > HPD_NONE &&
+		    dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_MARK_DISABLED &&
+		    connector->polled == DRM_CONNECTOR_POLL_HPD) {
+			pr_warn("HPD interrupt storm detected on connector %s disabling\n",
+				drm_get_connector_name(connector));
+			dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark = HPD_DISABLED;
+			connector->polled = DRM_CONNECTOR_POLL_CONNECT
+				| DRM_CONNECTOR_POLL_DISCONNECT;
+			connector_disabled = true;
+		}
+	}
+	if (connector_disabled)
+		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+	list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
+		if (intel_encoder->hot_plug)
+			intel_encoder->hot_plug(intel_encoder);
 
 	mutex_unlock(&mode_config->mutex);
 
@@ -578,13 +603,14 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
 	queue_work(dev_priv->wq, &dev_priv->rps.work);
 }
 
-static inline void hotplug_irq_storm_detect(struct drm_device *dev,
+static inline bool hotplug_irq_storm_detect(struct drm_device *dev,
 					    u32 hotplug_trigger,
 					    const u32 *hpd)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	unsigned long irqflags;
 	int i;
+	bool ret = false;
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
 
@@ -598,12 +624,15 @@ static inline void hotplug_irq_storm_detect(struct drm_device *dev,
 			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
 				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
 				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
+				ret = true;
 			} else
 				dev_priv->hpd_stats[i].hpd_cnt++;
 		}
 	}
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+	return ret;
 }
 
 static void gmbus_irq_handler(struct drm_device *dev)
@@ -679,7 +708,8 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 					 hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
+				if( hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915))
+					i915_hpd_irq_setup(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
@@ -709,7 +739,8 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
 
 	if (hotplug_trigger) {
-		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
+		if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx))
+			ibx_hpd_irq_setup(dev);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
 	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK)
@@ -757,7 +788,8 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
 
 	if (hotplug_trigger) {
-		hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
+		if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt))
+			ibx_hpd_irq_setup(dev);
 		queue_work(dev_priv->wq, &dev_priv->hotplug_work);
 	}
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
@@ -2034,12 +2066,14 @@ static void ibx_hpd_irq_setup(struct drm_device *dev)
 	if (HAS_PCH_IBX(dev)) {
 		mask &= ~SDE_HOTPLUG_MASK;
 		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-			mask |= hpd_ibx[intel_encoder->hpd_pin];
+			if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
+				mask |= hpd_ibx[intel_encoder->hpd_pin];
 		mask |= SDE_GMBUS | SDE_AUX_MASK;
 	} else {
 		mask &= ~SDE_HOTPLUG_MASK_CPT;
 		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-			mask |= hpd_cpt[intel_encoder->hpd_pin];
+			if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
+				mask |= hpd_cpt[intel_encoder->hpd_pin];
 		mask |= SDE_GMBUS_CPT | SDE_AUX_MASK_CPT;
 	}
 	I915_WRITE(SDEIIR, I915_READ(SDEIIR));
@@ -2505,7 +2539,8 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
+				if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915))
+					i915_hpd_irq_setup(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
@@ -2659,7 +2694,7 @@ static void i915_hpd_irq_setup(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct intel_encoder *encoder;
+	struct intel_encoder *intel_encoder;
 	u32 hotplug_en;
 
 	if (I915_HAS_HOTPLUG(dev)) {
@@ -2668,7 +2703,8 @@ static void i915_hpd_irq_setup(struct drm_device *dev)
 		/* Note HDMI and DP share hotplug bits */
 		/* enable bits are the same for all generations */
 		list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-			hotplug_en |= hpd_mask_i915[intel_encoder->hpd_pin];
+			if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
+				hotplug_en |= hpd_mask_i915[intel_encoder->hpd_pin];
 		/* Programming the CRT detection parameters tends
 		   to generate a spurious hotplug event about three
 		   seconds later.  So just do it once.
@@ -2742,8 +2778,9 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
 			if (hotplug_trigger) {
-				hotplug_irq_storm_detect(dev, hotplug_trigger,
-							 IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
+				if (hotplug_irq_storm_detect(dev, hotplug_trigger,
+							    IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965))
+					i915_hpd_irq_setup(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);
 			}
-- 
1.7.7

[PATCH v.3 11/12] DRM/i915: Add bit field to record which pins have received HPD events (v3)

[Egbert Eich]

This way it is possible to limit 're'-detect() of displays to connectors
which have received an HPD event.

v2: Reordered drm_i915_private: Move hpd_event_bits to hpd state tracking.
v3: Fix patch.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    1 +
 drivers/gpu/drm/i915/i915_irq.c |   47 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1fb7c44..d48d1e6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -933,6 +933,7 @@ typedef struct drm_i915_private {
 			HPD_MARK_DISABLED = 2
 		} hpd_mark;
 	} hpd_stats[HPD_NUM_PINS];
+	u32 hpd_event_bits;
 #define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
 	struct timer_list hotplug_reenable_timer;
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index fd68b21..9e8d5b4 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -330,6 +330,24 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
 						     crtc);
 }
 
+/**
+ * drm_helper_hpd_irq_single_connector_event() - call this function with mode_config.mutex lock held
+ */
+
+static int intel_hpd_irq_single_connector_event(struct drm_device *dev, struct drm_connector *connector)
+{
+	enum drm_connector_status old_status;
+
+	old_status = connector->status;
+
+	connector->status = connector->funcs->detect(connector, false);
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
+		      connector->base.id,
+		      drm_get_connector_name(connector),
+		      old_status, connector->status);
+	return (old_status != connector->status);
+}
+
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
@@ -344,6 +362,8 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_connector *connector;
 	unsigned long irqflags;
 	bool connector_disabled = false;
+	bool changed = false;
+	u32 hpd_event_bits;
 
 	/* HPD irq before everything is fully set up. */
 	if (!dev_priv->enable_hotplug_processing)
@@ -353,6 +373,9 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	hpd_event_bits = dev_priv->hpd_event_bits;
+	dev_priv->hpd_event_bits = 0;
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
 		intel_connector = to_intel_connector(connector);
 		intel_encoder = intel_connector->encoder;
@@ -366,6 +389,10 @@ static void i915_hotplug_work_func(struct work_struct *work)
 				| DRM_CONNECTOR_POLL_DISCONNECT;
 			connector_disabled = true;
 		}
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
+				      drm_get_connector_name(connector), intel_encoder->hpd_pin);
+		}
 	}
 	if (connector_disabled) {
 		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
@@ -375,14 +402,20 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
-	list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-		if (intel_encoder->hot_plug)
-			intel_encoder->hot_plug(intel_encoder);
-
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		intel_connector = to_intel_connector(connector);
+		intel_encoder = intel_connector->encoder;
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			if (intel_encoder->hot_plug)
+				intel_encoder->hot_plug(intel_encoder);
+			if (intel_hpd_irq_single_connector_event(dev, connector))
+				changed = true;
+		}
+	}
 	mutex_unlock(&mode_config->mutex);
 
-	/* Just fire off a uevent and let userspace tell us what to do */
-	drm_helper_hpd_irq_event(dev);
+	if (changed)
+		drm_kms_helper_hotplug_event(dev);
 }
 
 static void ironlake_handle_rps_change(struct drm_device *dev)
@@ -620,12 +653,14 @@ static inline bool hotplug_irq_storm_detect(struct drm_device *dev,
 	for (i = 1; i < HPD_NUM_PINS; i++) {
 		if ((hpd[i] & hotplug_trigger) &&
 		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
+			dev_priv->hpd_event_bits |= (1 << i);
 			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
 			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
 				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
 				dev_priv->hpd_stats[i].hpd_cnt = 0;
 			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
 				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
+				dev_priv->hpd_event_bits &= ~(1 << i);
 				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
 				ret = true;
 			} else
-- 
1.7.7

[PATCH v.3 12/12] DRM/i915: Only reprobe display on encoder which has received an HPD event.

[Egbert Eich]

Instead of calling into the DRM helper layer to poll all connectors for
changes in connected displays probe only those connectors which have
received a hotplug event.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_irq.c |   37 +++++++++++++++++++++++++++++++------
 1 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d65d76a..9e8d5b4 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -330,6 +330,24 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
 						     crtc);
 }
 
+/**
+ * drm_helper_hpd_irq_single_connector_event() - call this function with mode_config.mutex lock held
+ */
+
+static int intel_hpd_irq_single_connector_event(struct drm_device *dev, struct drm_connector *connector)
+{
+	enum drm_connector_status old_status;
+
+	old_status = connector->status;
+
+	connector->status = connector->funcs->detect(connector, false);
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
+		      connector->base.id,
+		      drm_get_connector_name(connector),
+		      old_status, connector->status);
+	return (old_status != connector->status);
+}
+
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
@@ -344,6 +362,7 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_connector *connector;
 	unsigned long irqflags;
 	bool connector_disabled = false;
+	bool changed = false;
 	u32 hpd_event_bits;
 
 	/* HPD irq before everything is fully set up. */
@@ -383,14 +402,20 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
-	list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-		if (intel_encoder->hot_plug)
-			intel_encoder->hot_plug(intel_encoder);
-
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		intel_connector = to_intel_connector(connector);
+		intel_encoder = intel_connector->encoder;
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			if (intel_encoder->hot_plug)
+				intel_encoder->hot_plug(intel_encoder);
+			if (intel_hpd_irq_single_connector_event(dev, connector))
+				changed = true;
+		}
+	}
 	mutex_unlock(&mode_config->mutex);
 
-	/* Just fire off a uevent and let userspace tell us what to do */
-	drm_helper_hpd_irq_event(dev);
+	if (changed)
+		drm_kms_helper_hotplug_event(dev);
 }
 
 static void ironlake_handle_rps_change(struct drm_device *dev)
-- 
1.7.7

Re: [PATCH v.3 11/12] DRM/i915: Add bit field to record which pins have received HPD events (v3)

[Egbert Eich]

On Tue, Mar 05, 2013 at 08:00:30AM -0500, Egbert Eich wrote:
> This way it is possible to limit 're'-detect() of displays to connectors
> which have received an HPD event.
> 
> v2: Reordered drm_i915_private: Move hpd_event_bits to hpd state tracking.
> v3: Fix patch.
> 

Oops, forget this patch. It's messed up.

Sorry,

	Egbert.

Re: [PATCH 2/8] drm/i915: Set hotplug_supported_flag for all chipset generations.

[Jesse Barnes]

On Thu, 10 Jan 2013 10:02:40 -0500
Egbert Eich <eich@suse.de> wrote:

> So far the hotplug_supported_mask in the struct drm_i915_private
> is only used for pre-Ironlake chipsets.
> This patch sets up the correct value for all generations.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_drv.h   |    4 ++
>  drivers/gpu/drm/i915/i915_irq.c   |   71 +++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_crt.c  |    2 +-
>  drivers/gpu/drm/i915/intel_dp.c   |    4 +--
>  drivers/gpu/drm/i915/intel_hdmi.c |    4 +--
>  drivers/gpu/drm/i915/intel_sdvo.c |   12 +------
>  6 files changed, 79 insertions(+), 18 deletions(-)

I like it.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Just a tiny style nitpick.  I'd prefer:

+	/* SDVO is treated separately */
+	if (IS_IVYBRIDGE(dev) ||
+	    IS_HASWELL(dev) ||
+	    (HAS_PCH_SPLIT(dev) && HAS_PCH_CPT(dev))) {

to be

+	/* SDVO is treated separately */
+	if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev) ||
+	    (HAS_PCH_SPLIT(dev) && HAS_PCH_CPT(dev))) {

instead because vertical space is precious.  But that's definitely not
worth delaying this patch over.

-- 
Jesse Barnes, Intel Open Source Technology Center

Re: [PATCH 3/8] drm/i915: Add hpd status bit to struct intel_connector.

[Jesse Barnes]

On Thu, 10 Jan 2013 10:02:41 -0500
Egbert Eich <eich@suse.de> wrote:

> To be able to map an HPD interrupt to a connector add the
> hpd status bit to the intel_connector structure.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/intel_crt.c  |    3 ++-
>  drivers/gpu/drm/i915/intel_dp.c   |    3 ++-
>  drivers/gpu/drm/i915/intel_drv.h  |    3 +++
>  drivers/gpu/drm/i915/intel_hdmi.c |    3 ++-
>  drivers/gpu/drm/i915/intel_sdvo.c |   11 ++++++++++-
>  5 files changed, 19 insertions(+), 4 deletions(-)

Another nice simple addition.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center

Re: [PATCH 4/8] drm/i915: Add Hotplug IRQ Storm detection.

[Jesse Barnes]

On Thu, 10 Jan 2013 10:02:42 -0500
Egbert Eich <eich@suse.de> wrote:

> +		if (hotplug_trigger & intel_connector->hpd_status_bit) {
> +			if (jiffies > (intel_connector->last_hpd_jiffies + msecs_to_jiffies(1000)) ||
> +			    jiffies < intel_connector->last_hpd_jiffies) {

Can you use time_after() here instead?

Otherwise this looks really nice.  We should get it lots of testing and
soak time.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center

Re: [PATCH 5/8] drm/i915: Move hotplug interrupt enable for i915/i965/valleyview into a separate function.

[Jesse Barnes]

On Thu, 10 Jan 2013 10:02:43 -0500
Egbert Eich <eich@suse.de> wrote:

> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_irq.c |  178 ++++++++++++++++++++++----------------
>  1 files changed, 103 insertions(+), 75 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 4e75df0..356472f 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -567,6 +567,32 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
>  	queue_work(dev_priv->wq, &dev_priv->rps.work);
>  }
>  
> +static void valleyview_enable_hotplug_irq(struct drm_device *dev)

Given how you use these later, _reset_hotplug_irq or _update_hotplug_irq
might be a better name, but that's no biggie.

Seems like a nice cleanup by itself even.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center

Re: [PATCH v.2 01/12] DRM/i915: Remove valleyview_hpd_irq_setup.

[Jesse Barnes]

On Mon, 25 Feb 2013 12:06:48 -0500
Egbert Eich <eich@suse.de> wrote:

> It's basically identical to i915_hpd_irq_setup().
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_irq.c |   26 +-------------------------
>  1 files changed, 1 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 2cd97d1..5fd3267 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2113,30 +2113,6 @@ static int valleyview_irq_postinstall(struct drm_device *dev)
>  	return 0;
>  }
>  
> -static void valleyview_hpd_irq_setup(struct drm_device *dev)
> -{
> -	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
> -	u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
> -
> -	/* Note HDMI and DP share bits */
> -	if (dev_priv->hotplug_supported_mask & PORTB_HOTPLUG_INT_STATUS)
> -		hotplug_en |= PORTB_HOTPLUG_INT_EN;
> -	if (dev_priv->hotplug_supported_mask & PORTC_HOTPLUG_INT_STATUS)
> -		hotplug_en |= PORTC_HOTPLUG_INT_EN;
> -	if (dev_priv->hotplug_supported_mask & PORTD_HOTPLUG_INT_STATUS)
> -		hotplug_en |= PORTD_HOTPLUG_INT_EN;
> -	if (dev_priv->hotplug_supported_mask & SDVOC_HOTPLUG_INT_STATUS_I915)
> -		hotplug_en |= SDVOC_HOTPLUG_INT_EN;
> -	if (dev_priv->hotplug_supported_mask & SDVOB_HOTPLUG_INT_STATUS_I915)
> -		hotplug_en |= SDVOB_HOTPLUG_INT_EN;
> -	if (dev_priv->hotplug_supported_mask & CRT_HOTPLUG_INT_STATUS) {
> -		hotplug_en |= CRT_HOTPLUG_INT_EN;
> -		hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
> -	}
> -
> -	I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
> -}
> -
>  static void valleyview_irq_uninstall(struct drm_device *dev)
>  {
>  	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
> @@ -2835,7 +2811,7 @@ void intel_irq_init(struct drm_device *dev)
>  		dev->driver->irq_uninstall = valleyview_irq_uninstall;
>  		dev->driver->enable_vblank = valleyview_enable_vblank;
>  		dev->driver->disable_vblank = valleyview_disable_vblank;
> -		dev_priv->display.hpd_irq_setup = valleyview_hpd_irq_setup;
> +		dev_priv->display.hpd_irq_setup = i915_hpd_irq_setup;
>  	} else if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
>  		/* Share pre & uninstall handlers with ILK/SNB */
>  		dev->driver->irq_handler = ivybridge_irq_handler;

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center

Re: [PATCH v.2 02/12] DRM/I915: Add enum hpd_pin to intel_encoder.

[Jesse Barnes]

On Mon, 25 Feb 2013 12:06:49 -0500
Egbert Eich <eich@suse.de> wrote:

> To clean up hotplug support we add a new enum to intel_encoder:
> enum hpd_pin. It allows the encoder to request a hpd line but leave
> the details which IRQ is responsible on which chipset generation
> to i915_irq.c.
> This way requesting hotplug support will become really simple on
> the encoder/connector level.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_drv.h   |   13 +++++++++++++
>  drivers/gpu/drm/i915/intel_crt.c  |    2 ++
>  drivers/gpu/drm/i915/intel_dp.c   |    4 ++++
>  drivers/gpu/drm/i915/intel_drv.h  |    1 +
>  drivers/gpu/drm/i915/intel_hdmi.c |    4 ++++
>  drivers/gpu/drm/i915/intel_sdvo.c |    3 +++
>  6 files changed, 27 insertions(+), 0 deletions(-)

Even better than the last one I suppose...

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center

Re: [PATCH v.2 03/12] DRM/i915: Convert HPD interrupts to make use of HPD pin assignment in encoders.

[Jesse Barnes]

On Mon, 25 Feb 2013 12:06:50 -0500
Egbert Eich <eich@suse.de> wrote:

> This allows to enable HPD interrupts for individual pins to only receive
> hotplug events from lines which are connected and working.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---

In reviewing the old one, I thought tables might be nice, but on
seeing it I'm not sure.  I think they're about the same.  So I'm ok
with either.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center

Re: [PATCH v.2 05/12] DRM/i915: Get rid if the 'hotplug_supported_mask' in struct drm_i915_private.

[Daniel Vetter]

On Mon, Feb 25, 2013 at 12:06:52PM -0500, Egbert Eich wrote:
> Now since we have replaced the bits to show interest in hotplug IRQs
> we can go and nuke the 'hotplug_supported_mask'.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>

I've applied your patch up to this one. Patch four needed some manual
convincing to fit correctly, but the new hpd infrastructure is now in
place.

To get the actual hpd irq storm detection going I think it'd be good to
resend the remaining patches on top of latest drm-intel-nightly. I'll try
to yell at people a bit harder to review things more timely this time
around.

Thanks for the patches.

Cheers, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH v.2 05/12] DRM/i915: Get rid if the 'hotplug_supported_mask' in struct drm_i915_private.

[Egbert Eich]

Daniel Vetter writes:
 > On Mon, Feb 25, 2013 at 12:06:52PM -0500, Egbert Eich wrote:
 > > Now since we have replaced the bits to show interest in hotplug IRQs
 > > we can go and nuke the 'hotplug_supported_mask'.
 > > 
 > > Signed-off-by: Egbert Eich <eich@suse.de>
 > 
 > I've applied your patch up to this one. Patch four needed some manual
 > convincing to fit correctly, but the new hpd infrastructure is now in
 > place.
 > 
 > To get the actual hpd irq storm detection going I think it'd be good to
 > resend the remaining patches on top of latest drm-intel-nightly. I'll try
 > to yell at people a bit harder to review things more timely this time
 > around.
 > 
 > Thanks for the patches.

Thanks guys for reviewing the patches. I will try to spare some time tonight
to look into the issues that came up. 
I got dragged into other tasks as well so I didn't even find the time to 
follow up on the patches myself.

For now I need to go back and debug yet another issue with SDVO on GM45 :(

Cheers,
	Egbert.

Re: [PATCH v.2 10/12] DRM/i915: Add Reenable Timer to turn Hotplug Detection back on.

[Daniel Vetter]

On Mon, Feb 25, 2013 at 12:06:57PM -0500, Egbert Eich wrote:
> We disable hoptplug detection when we encounter a hotplug event
> storm. Still hotplug detection is required on some outputs (like
> Display Port). The interrupt storm may be only temporary (on certain
> Dell Laptops for instance it happens at certain charging states of
> the system). Thus we enable it after a certain grace period (2 minutes).
> Should the interrupt storm persist it will be detected immediately
> and it will be disabled again.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>

Oops, just noticed that you have an ibx_hpd_irq_setup patch, too ;-) I
think I'll go with since that one's just gotten a bit a beating in review
from Ville. Hopfully that's not too ugly to rebase over ...
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_drv.h |    2 +
>  drivers/gpu/drm/i915/i915_irq.c |   53 ++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 54 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 6ca742d..58bee7a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1068,6 +1068,8 @@ typedef struct drm_i915_private {
>  			HPD_MARK_DISABLED = 2
>  		} hpd_mark;
>  	} hpd_stats[HPD_NUM_PINS];
> +#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
> +	struct timer_list hotplug_reenable_timer;
>  } drm_i915_private_t;
>  
>  /* Iterate over initialised rings */
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 8878fdd..ba598e3 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -376,8 +376,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
>  			connector_disabled = true;
>  		}
>  	}
> -	if (connector_disabled)
> +	if (connector_disabled) {
>  		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
> +		mod_timer(&dev_priv->hotplug_reenable_timer,
> +			  jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
> +	}
>  
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
>  
> @@ -2253,6 +2256,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	for_each_pipe(pipe)
>  		I915_WRITE(PIPESTAT(pipe), 0xffff);
>  
> @@ -2274,6 +2279,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	I915_WRITE(HWSTAM, 0xffffffff);
>  
>  	I915_WRITE(DEIMR, 0xffffffff);
> @@ -2612,6 +2619,8 @@ static void i915_irq_uninstall(struct drm_device * dev)
>  	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
>  	int pipe;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	if (I915_HAS_HOTPLUG(dev)) {
>  		I915_WRITE(PORT_HOTPLUG_EN, 0);
>  		I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
> @@ -2860,6 +2869,8 @@ static void i965_irq_uninstall(struct drm_device * dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	I915_WRITE(PORT_HOTPLUG_EN, 0);
>  	I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
>  
> @@ -2875,6 +2886,44 @@ static void i965_irq_uninstall(struct drm_device * dev)
>  	I915_WRITE(IIR, I915_READ(IIR));
>  }
>  
> +static void i915_reenable_hotplug_timer_func(unsigned long data)
> +{
> +	drm_i915_private_t *dev_priv = (drm_i915_private_t *)data;
> +	struct drm_device *dev = dev_priv->dev;
> +	struct drm_mode_config *mode_config = &dev->mode_config;
> +	unsigned long irqflags;
> +	int i;
> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +	for (i = 1; i < HPD_NUM_PINS; i++) {
> +		if (dev_priv->hpd_stats[i].hpd_mark == HPD_MARK_DISABLED) {
> +			struct drm_connector *connector;
> +
> +			dev_priv->hpd_stats[i].hpd_mark = HPD_ENABLED;
> +			list_for_each_entry(connector, &mode_config->connector_list, head) {
> +				struct intel_connector *intel_connector = to_intel_connector(connector);
> +
> +				if (intel_connector->encoder->hpd_pin == i) {
> +					if (connector->polled != intel_connector->polled)
> +						DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
> +							 drm_get_connector_name(connector));
> +					connector->polled = intel_connector->polled;
> +					if (!connector->polled)
> +						connector->polled = DRM_CONNECTOR_POLL_HPD;
> +				}
> +			}
> +
> +			if (IS_HASWELL(dev) ||
> +			    IS_IVYBRIDGE(dev) ||
> +			    (HAS_PCH_SPLIT(dev)))
> +				ibx_hpd_irq_setup(dev);
> +			else
> +				i915_hpd_irq_setup(dev);
> +		}
> +	}
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> +
>  void intel_irq_init(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -2887,6 +2936,8 @@ void intel_irq_init(struct drm_device *dev)
>  	setup_timer(&dev_priv->gpu_error.hangcheck_timer,
>  		    i915_hangcheck_elapsed,
>  		    (unsigned long) dev);
> +	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
> +		    (unsigned long) dev_priv);
>  
>  	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
>  
> -- 
> 1.7.7
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch