[PATCH v4] drm/i915/edp: Add a T12 panel delay quirk to fix DP AUX CH timeouts

[Manasi Navare <manasi.d.navare@intel.com>]

This patch fixes the DP AUX CH timeouts observed during CI IGT
tests thus fixing the CI failures. This is done by adding a
quirk for a particular PCI device that requires the panel power
cycle delay (T12) to be set to 800ms which is 300msecs more than
the minimum value specified in the eDP spec. So a quirk is
implemented for that specific PCI device.

v4:
* Add Bugzilla links for FDO bugs in the commit message (Ville, Jani)
v3:
* Change some comments, specify the delay as 800 * 10 (Ville)
v2:
* Change the function and variable names to from PPS_T12_
to _T12 since it is a T12 delay (Clint)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101144
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101154
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101167
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101515
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Clinton Taylor <clinton.a.taylor@intel.com>
Acked-by: Ville Syrjala <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h      |  1 +
 drivers/gpu/drm/i915/intel_display.c | 14 ++++++++++++++
 drivers/gpu/drm/i915/intel_dp.c      | 11 +++++++++++
 3 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index effbe4f..4bef5d3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1167,6 +1167,7 @@ enum intel_sbi_destination {
 #define QUIRK_INVERT_BRIGHTNESS (1<<2)
 #define QUIRK_BACKLIGHT_PRESENT (1<<3)
 #define QUIRK_PIN_SWIZZLED_PAGES (1<<5)
+#define QUIRK_INCREASE_T12_DELAY (1<<6)
 
 struct intel_fbdev;
 struct intel_fbc_work;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4e03ca6..87dfde9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -14765,6 +14765,17 @@ static void quirk_backlight_present(struct drm_device *dev)
 	DRM_INFO("applying backlight present quirk\n");
 }
 
+/* Toshiba Satellite P50-C-18C requires T12 delay to be min 800ms
+ * which is 300 ms greater than eDP spec T12 min.
+ */
+static void quirk_increase_t12_delay(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = to_i915(dev);
+
+	dev_priv->quirks |= QUIRK_INCREASE_T12_DELAY;
+	DRM_INFO("Applying T12 delay quirk\n");
+}
+
 struct intel_quirk {
 	int device;
 	int subsystem_vendor;
@@ -14848,6 +14859,9 @@ static struct intel_quirk intel_quirks[] = {
 
 	/* Dell Chromebook 11 (2015 version) */
 	{ 0x0a16, 0x1028, 0x0a35, quirk_backlight_present },
+
+	/* Toshiba Satellite P50-C-18C */
+	{ 0x191B, 0x1179, 0xF840, quirk_increase_t12_delay },
 };
 
 static void intel_init_quirks(struct drm_device *dev)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 67bc8a7a..538950c 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5230,6 +5230,17 @@ intel_dp_init_panel_power_sequencer(struct drm_device *dev,
 	intel_pps_dump_state("cur", &cur);
 
 	vbt = dev_priv->vbt.edp.pps;
+	/* On Toshiba Satellite P50-C-18C system the VBT T12 delay
+	 * of 500ms appears to be too short. Ocassionally the panel
+	 * just fails to power back on. Increasing the delay to 800ms
+	 * seems sufficient to avoid this problem.
+	 */
+	if (dev_priv->quirks & QUIRK_INCREASE_T12_DELAY) {
+
+		vbt.t11_t12 = max_t(u16, vbt.t11_t12, 800 * 10);
+		DRM_DEBUG_KMS("Increasing T12 panel delay as per the quirk to %d\n",
+			      vbt.t11_t12);
+	}
 	/* T11_T12 delay is special and actually in units of 100ms, but zero
 	 * based in the hw (so we need to add 100 ms). But the sw vbt
 	 * table multiplies it with 1000 to make it in units of 100usec,
-- 
2.1.4

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