[PATCH v4 0/6] drm: add per-connector hotplug events

[PATCH v4 0/6] drm: add per-connector hotplug events

[Simon Ser]

When a uevent only updates a single connector, add a CONNECTOR property
to the uevent. This allows user-space to ignore other connectors when
handling the uevent. This is purely an optimization, drivers can still
send a uevent without the CONNECTOR property.

The CONNECTOR property is already set when sending HDCP property update
uevents, see drm_sysfs_connector_status_event.

This has been tested with a wlroots patch [1].

amdgpu and the probe-helper has been updated to use these new fine-grained
uevents.

Changes in v4: address comments from Ville, Maxime and Sam.

Simon Ser (6):
  drm/sysfs: introduce drm_sysfs_connector_hotplug_event
  drm/probe-helper: add drm_kms_helper_connector_hotplug_event
  drm/connector: use drm_sysfs_connector_hotplug_event
  amdgpu: use drm_kms_helper_connector_hotplug_event
  drm/probe-helper: use drm_kms_helper_connector_hotplug_event
  i915/display/dp: send a more fine-grained link-status uevent

 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  8 ++--
 .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c |  4 +-
 drivers/gpu/drm/drm_connector.c               |  2 +-
 drivers/gpu/drm/drm_probe_helper.c            | 48 +++++++++++++++----
 drivers/gpu/drm/drm_sysfs.c                   | 25 ++++++++++
 drivers/gpu/drm/i915/display/intel_dp.c       |  2 +-
 include/drm/drm_probe_helper.h                |  1 +
 include/drm/drm_sysfs.h                       |  1 +
 8 files changed, 75 insertions(+), 16 deletions(-)


base-commit: f6632721cd6231e1bf28b5317dcc7543e43359f7
-- 
2.33.1

[PATCH v4 1/6] drm/sysfs: introduce drm_sysfs_connector_hotplug_event

[Simon Ser]

This function sends a hotplug uevent with a CONNECTOR property.

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Harry Wentland <harry.wentland@amd.com>
---
 drivers/gpu/drm/drm_sysfs.c | 25 +++++++++++++++++++++++++
 include/drm/drm_sysfs.h     |  1 +
 2 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index 76ff6ec3421b..430e00b16eec 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -409,6 +409,31 @@ void drm_sysfs_hotplug_event(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_sysfs_hotplug_event);
 
+/**
+ * drm_sysfs_connector_hotplug_event - generate a DRM uevent for any connector
+ * change
+ * @connector: connector which has changed
+ *
+ * Send a uevent for the DRM connector specified by @connector. This will send
+ * a uevent with the properties HOTPLUG=1 and CONNECTOR.
+ */
+void drm_sysfs_connector_hotplug_event(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	char hotplug_str[] = "HOTPLUG=1", conn_id[21];
+	char *envp[] = { hotplug_str, conn_id, NULL };
+
+	snprintf(conn_id, sizeof(conn_id),
+		 "CONNECTOR=%u", connector->base.id);
+
+	drm_dbg_kms(connector->dev,
+		    "[CONNECTOR:%d:%s] generating connector hotplug event\n",
+		    connector->base.id, connector->name);
+
+	kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
+}
+EXPORT_SYMBOL(drm_sysfs_connector_hotplug_event);
+
 /**
  * drm_sysfs_connector_status_event - generate a DRM uevent for connector
  * property status change
diff --git a/include/drm/drm_sysfs.h b/include/drm/drm_sysfs.h
index d454ef617b2c..6273cac44e47 100644
--- a/include/drm/drm_sysfs.h
+++ b/include/drm/drm_sysfs.h
@@ -11,6 +11,7 @@ int drm_class_device_register(struct device *dev);
 void drm_class_device_unregister(struct device *dev);
 
 void drm_sysfs_hotplug_event(struct drm_device *dev);
+void drm_sysfs_connector_hotplug_event(struct drm_connector *connector);
 void drm_sysfs_connector_status_event(struct drm_connector *connector,
 				      struct drm_property *property);
 #endif
-- 
2.33.1

[PATCH v4 2/6] drm/probe-helper: add drm_kms_helper_connector_hotplug_event

[Simon Ser]

This function is the same as drm_kms_helper_hotplug_event, but takes
a connector instead of a device.

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Harry Wentland <harry.wentland@amd.com>
---
 drivers/gpu/drm/drm_probe_helper.c | 23 +++++++++++++++++++++++
 include/drm/drm_probe_helper.h     |  1 +
 2 files changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 61d5c57f23e1..3aef3b188c99 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -604,6 +604,9 @@ EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
  *
  * This function must be called from process context with no mode
  * setting locks held.
+ *
+ * If only a single connector has changed, consider calling
+ * drm_kms_helper_connector_hotplug_event() instead.
  */
 void drm_kms_helper_hotplug_event(struct drm_device *dev)
 {
@@ -616,6 +619,26 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
 
+/**
+ * drm_kms_helper_connector_hotplug_event - fire off a KMS connector hotplug event
+ * @connector: drm_connector which has changed
+ *
+ * This is the same as drm_kms_helper_hotplug_event(), except it fires a more
+ * fine-grained uevent for a single connector.
+ */
+void drm_kms_helper_connector_hotplug_event(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+
+	/* send a uevent + call fbdev */
+	drm_sysfs_connector_hotplug_event(connector);
+	if (dev->mode_config.funcs->output_poll_changed)
+		dev->mode_config.funcs->output_poll_changed(dev);
+
+	drm_client_dev_hotplug(dev);
+}
+EXPORT_SYMBOL(drm_kms_helper_connector_hotplug_event);
+
 static void output_poll_execute(struct work_struct *work)
 {
 	struct delayed_work *delayed_work = to_delayed_work(work);
diff --git a/include/drm/drm_probe_helper.h b/include/drm/drm_probe_helper.h
index 04c57564c397..48300aa6ca71 100644
--- a/include/drm/drm_probe_helper.h
+++ b/include/drm/drm_probe_helper.h
@@ -20,6 +20,7 @@ void drm_kms_helper_poll_fini(struct drm_device *dev);
 bool drm_helper_hpd_irq_event(struct drm_device *dev);
 bool drm_connector_helper_hpd_irq_event(struct drm_connector *connector);
 void drm_kms_helper_hotplug_event(struct drm_device *dev);
+void drm_kms_helper_connector_hotplug_event(struct drm_connector *connector);
 
 void drm_kms_helper_poll_disable(struct drm_device *dev);
 void drm_kms_helper_poll_enable(struct drm_device *dev);
-- 
2.33.1

[PATCH v4 3/6] drm/connector: use drm_sysfs_connector_hotplug_event

[Simon Ser]

In drm_connector_register, use drm_sysfs_connector_hotplug_event
instead of drm_sysfs_hotplug_event, because the hotplug event
only updates a single connector.

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Harry Wentland <harry.wentland@amd.com>
---
 drivers/gpu/drm/drm_connector.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index ec3973e8963c..a50c82bc2b2f 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -547,7 +547,7 @@ int drm_connector_register(struct drm_connector *connector)
 	connector->registration_state = DRM_CONNECTOR_REGISTERED;
 
 	/* Let userspace know we have a new connector */
-	drm_sysfs_hotplug_event(connector->dev);
+	drm_sysfs_connector_hotplug_event(connector);
 
 	if (connector->privacy_screen)
 		drm_privacy_screen_register_notifier(connector->privacy_screen,
-- 
2.33.1

[PATCH v4 4/6] amdgpu: use drm_kms_helper_connector_hotplug_event

[Simon Ser]

When updating a single connector, use
drm_kms_helper_connector_hotplug_event instead of
drm_kms_helper_hotplug_event.

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c         | 8 ++++----
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 9b1fc54555ee..c261e57d9a22 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2652,7 +2652,7 @@ static void handle_hpd_irq(void *param)
 		drm_modeset_unlock_all(dev);
 
 		if (aconnector->base.force == DRM_FORCE_UNSPECIFIED)
-			drm_kms_helper_hotplug_event(dev);
+			drm_kms_helper_connector_hotplug_event(connector);
 
 	} else if (dc_link_detect(aconnector->dc_link, DETECT_REASON_HPD)) {
 		if (new_connection_type == dc_connection_none &&
@@ -2666,7 +2666,7 @@ static void handle_hpd_irq(void *param)
 		drm_modeset_unlock_all(dev);
 
 		if (aconnector->base.force == DRM_FORCE_UNSPECIFIED)
-			drm_kms_helper_hotplug_event(dev);
+			drm_kms_helper_connector_hotplug_event(connector);
 	}
 	mutex_unlock(&aconnector->hpd_lock);
 
@@ -2833,7 +2833,7 @@ static void handle_hpd_rx_irq(void *param)
 			dm_restore_drm_connector_state(dev, connector);
 			drm_modeset_unlock_all(dev);
 
-			drm_kms_helper_hotplug_event(dev);
+			drm_kms_helper_connector_hotplug_event(connector);
 		} else if (dc_link_detect(dc_link, DETECT_REASON_HPDRX)) {
 
 			if (aconnector->fake_enable)
@@ -2846,7 +2846,7 @@ static void handle_hpd_rx_irq(void *param)
 			dm_restore_drm_connector_state(dev, connector);
 			drm_modeset_unlock_all(dev);
 
-			drm_kms_helper_hotplug_event(dev);
+			drm_kms_helper_connector_hotplug_event(connector);
 		}
 	}
 #ifdef CONFIG_DRM_AMD_DC_HDCP
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
index 87daa78a32b8..23e789855d17 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
@@ -1241,7 +1241,7 @@ static ssize_t trigger_hotplug(struct file *f, const char __user *buf,
 		dm_restore_drm_connector_state(dev, connector);
 		drm_modeset_unlock_all(dev);
 
-		drm_kms_helper_hotplug_event(dev);
+		drm_kms_helper_connector_hotplug_event(connector);
 	} else if (param[0] == 0) {
 		if (!aconnector->dc_link)
 			goto unlock;
@@ -1263,7 +1263,7 @@ static ssize_t trigger_hotplug(struct file *f, const char __user *buf,
 		dm_restore_drm_connector_state(dev, connector);
 		drm_modeset_unlock_all(dev);
 
-		drm_kms_helper_hotplug_event(dev);
+		drm_kms_helper_connector_hotplug_event(connector);
 	}
 
 unlock:
-- 
2.33.1

[PATCH v4 5/6] drm/probe-helper: use drm_kms_helper_connector_hotplug_event

[Simon Ser]

If an hotplug event only updates a single connector, use
drm_kms_helper_connector_hotplug_event instead of
drm_kms_helper_hotplug_event.

Changes in v4:
- Simplify loop logic (Ville, Sam)
- Update drm_connector_helper_hpd_irq_event (Maxime)

Signed-off-by: Simon Ser <contact@emersion.fr>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/drm_probe_helper.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 3aef3b188c99..682359512996 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -888,7 +888,7 @@ bool drm_connector_helper_hpd_irq_event(struct drm_connector *connector)
 	mutex_unlock(&dev->mode_config.mutex);
 
 	if (changed) {
-		drm_kms_helper_hotplug_event(dev);
+		drm_kms_helper_connector_hotplug_event(connector);
 		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Sent hotplug event\n",
 			    connector->base.id,
 			    connector->name);
@@ -927,9 +927,9 @@ EXPORT_SYMBOL(drm_connector_helper_hpd_irq_event);
  */
 bool drm_helper_hpd_irq_event(struct drm_device *dev)
 {
-	struct drm_connector *connector;
+	struct drm_connector *connector, *first_changed_connector = NULL;
 	struct drm_connector_list_iter conn_iter;
-	bool changed = false;
+	int changed = 0;
 
 	if (!dev->mode_config.poll_enabled)
 		return false;
@@ -941,16 +941,25 @@ bool drm_helper_hpd_irq_event(struct drm_device *dev)
 		if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
 			continue;
 
-		if (check_connector_changed(connector))
-			changed = true;
+		if (check_connector_changed(connector)) {
+			if (!first_changed_connector) {
+				drm_connector_get(connector);
+				first_changed_connector = connector;
+			}
+
+			changed++;
+		}
 	}
 	drm_connector_list_iter_end(&conn_iter);
 	mutex_unlock(&dev->mode_config.mutex);
 
-	if (changed) {
+	if (changed == 1)
+		drm_kms_helper_connector_hotplug_event(first_changed_connector);
+	else if (changed > 0)
 		drm_kms_helper_hotplug_event(dev);
-		DRM_DEBUG_KMS("Sent hotplug event\n");
-	}
+
+	if (first_changed_connector)
+		drm_connector_put(first_changed_connector);
 
 	return changed;
 }
-- 
2.33.1

[PATCH v4 6/6] i915/display/dp: send a more fine-grained link-status uevent

[Simon Ser]

When link-status changes, send a hotplug uevent which contains the
connector ID. That way, user-space can more easily figure out that
only this connector has been updated.

Changes in v4: avoid sending two uevents (Ville)

Signed-off-by: Simon Ser <contact@emersion.fr>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 04175f359fd6..8b81a709d33b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5263,7 +5263,7 @@ static void intel_dp_modeset_retry_work_fn(struct work_struct *work)
 					       DRM_MODE_LINK_STATUS_BAD);
 	mutex_unlock(&connector->dev->mode_config.mutex);
 	/* Send Hotplug uevent so userspace can reprobe */
-	drm_kms_helper_hotplug_event(connector->dev);
+	drm_kms_helper_connector_hotplug_event(connector);
 }
 
 bool
-- 
2.33.1

Re: [PATCH v4 5/6] drm/probe-helper: use drm_kms_helper_connector_hotplug_event

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 578 bytes --]

On Mon, Oct 18, 2021 at 08:47:30AM +0000, Simon Ser wrote:
> If an hotplug event only updates a single connector, use
> drm_kms_helper_connector_hotplug_event instead of
> drm_kms_helper_hotplug_event.
> 
> Changes in v4:
> - Simplify loop logic (Ville, Sam)
> - Update drm_connector_helper_hpd_irq_event (Maxime)
> 
> Signed-off-by: Simon Ser <contact@emersion.fr>
> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: Maxime Ripard <maxime@cerno.tech>

Reviewed-by: Maxime Ripard <maxime@cerno.tech>

Thanks!
Maxime

[-- Attachment #2: signature.asc --]
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Re: [PATCH v4 5/6] drm/probe-helper: use drm_kms_helper_connector_hotplug_event

[Sam Ravnborg]

Hi Simon,

On Mon, Oct 18, 2021 at 08:47:30AM +0000, Simon Ser wrote:
> If an hotplug event only updates a single connector, use
> drm_kms_helper_connector_hotplug_event instead of
> drm_kms_helper_hotplug_event.
> 
> Changes in v4:
> - Simplify loop logic (Ville, Sam)
> - Update drm_connector_helper_hpd_irq_event (Maxime)
> 
> Signed-off-by: Simon Ser <contact@emersion.fr>
> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: Maxime Ripard <maxime@cerno.tech>

Thanks, I like this better.
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

Maybe I am late and this was already applied...

	Sam

Re: [PATCH v4 6/6] i915/display/dp: send a more fine-grained link-status uevent

[Ville Syrjälä]

On Mon, Oct 18, 2021 at 08:47:31AM +0000, Simon Ser wrote:
> When link-status changes, send a hotplug uevent which contains the
> connector ID. That way, user-space can more easily figure out that
> only this connector has been updated.
> 
> Changes in v4: avoid sending two uevents (Ville)
> 
> Signed-off-by: Simon Ser <contact@emersion.fr>
> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 04175f359fd6..8b81a709d33b 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5263,7 +5263,7 @@ static void intel_dp_modeset_retry_work_fn(struct work_struct *work)
>  					       DRM_MODE_LINK_STATUS_BAD);
>  	mutex_unlock(&connector->dev->mode_config.mutex);
>  	/* Send Hotplug uevent so userspace can reprobe */
> -	drm_kms_helper_hotplug_event(connector->dev);
> +	drm_kms_helper_connector_hotplug_event(connector);
>  }
>  
>  bool
> -- 
> 2.33.1
> 

-- 
Ville Syrjälä
Intel