Re: [Intel-gfx] [v3] drm/i915: Add detection of changing of edid on between suspend and resume

On Fri, 2018-08-10 at 13:02 +0000, Lisovskiy, Stanislav wrote:

On Thu, 2018-08-09 at 14:13 +0300, Gwan-gyeong Mun wrote:

...

The hotplug detection routine of i915 uses drm_helper_hpd_irq_event(). This helper can detect changing of status of connector, but it can not detect changing of edid.

Following scenario requires detection of changing of edid.

1) plug display device to a connector  2) system suspend  3) unplug 1)'s display device and plug the other display device to a connector  4) system resume

It adds edid check routine when a connector status still remains as "connector_status_connected".

v2: Add NULL check before comparing of EDIDs.

Testcase: igt/kms_chamelium/hdmi-edid-change-during-hibernate Testcase: igt/kms_chamelium/hdmi-edid-change-during-suspend Testcase: igt/kms_chamelium/dp-edid-change-during-hibernate Testcase: igt/kms_chamelium/dp-edid-change-during-suspend

Signed-off-by: Gwan-gyeong Mun gwan-gyeong.mun@intel.com

drivers/gpu/drm/i915/intel_hotplug.c | 84 +++++++++++++++++++++++++++-  1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c index 648a13c6043c..965f2d771fc0 100644 --- a/drivers/gpu/drm/i915/intel_hotplug.c +++ b/drivers/gpu/drm/i915/intel_hotplug.c @@ -507,6 +507,88 @@ void intel_hpd_init(struct drm_i915_private *dev_priv)   }  }   +/**

• • intel_hpd_irq_event - hotplug processing
• • @dev: drm_device
• • Drivers can use this function to run a detect cycle on all

connectors which

• • have the DRM_CONNECTOR_POLL_HPD flag set in their &polled

member. All other

• • connectors are ignored, which is useful to avoid reprobing

fixed panels.

• • This function is useful for drivers which can't or don't track

hotplug interrupts

• • for each connector. This function is based on

drm_helper_hpd_irq_event() helper

• • function and besides it adds edid check routine when a

connector status still

• • remains as "connector_status_connected".
• • Following scenario requires detection of changing of edid.
• *  1) plug display device to a connector
• *  2) system suspend
• *  3) unplug 1)'s display device and plug the other display

device to a connector

• *  4) system resume
• • This function must be called from process context with no mode
• • setting locks held.
• • Note that a connector can be both polled and probed from the

hotplug handler,

• • in case the hotplug interrupt is known to be unreliable.
• */

+static bool intel_hpd_irq_event(struct drm_device *dev) +{

• struct drm_connector *connector;
• struct drm_connector_list_iter conn_iter;
• enum drm_connector_status old_status, cur_status;
• struct edid *old_edid;
• bool changed = false;
• if (!dev->mode_config.poll_enabled)

• return false;
  

• mutex_lock(&dev->mode_config.mutex);
• drm_connector_list_iter_begin(dev, &conn_iter);
• drm_for_each_connector_iter(connector, &conn_iter) {

• /* Only handle HPD capable connectors. */
  

• if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
  

• 	continue;
  

• old_status = connector->status;
  

• old_edid = to_intel_connector(connector)-
  

...

detect_edid;

• cur_status = drm_helper_probe_detect(connector,
  

NULL, false);

• DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated
  

from %s to %s\n",

• 	      connector->base.id, connector->name,
  

• 	      drm_get_connector_status_name(old_st
  

at us),

• 	      drm_get_connector_status_name(cur_st
  

at us));

• if (old_status != cur_status)
  

• 	changed = true;
  

• /* Check changing of edid when a connector status
  

still remains

•  * as "connector_status_connected".
  

•  */
  

• if (old_status == cur_status &&
  

•     cur_status == connector_status_connected) {
  

• 	struct edid *cur_edid =
  

to_intel_connector(connector)->detect_edid;

• 	if (!old_edid || !cur_edid)
  

• 		continue;
  

• 	if (memcmp(old_edid, cur_edid,
  

sizeof(*cur_edid))) {

• 		changed = true;
  

• 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s]
  

edid updated\n",

• 			      connector->base.id,
  

• 			      connector->name);
  

• 	}
  

• }
  

• }
• drm_connector_list_iter_end(&conn_iter);
• mutex_unlock(&dev->mode_config.mutex);
• if (changed)

• drm_kms_helper_hotplug_event(dev);
  

• return changed;

+}

static void i915_hpd_poll_init_work(struct work_struct *work)  {   struct drm_i915_private *dev_priv = @@ -552,7 +634,7 @@ static void i915_hpd_poll_init_work(struct work_struct *work)    * in the middle of disabling polling    */   if (!enabled)

• drm_helper_hpd_irq_event(dev);
  

• intel_hpd_irq_event(dev);
  

}

Just wondering, as I saw previously drm_helper_hpd_irq_event function was used, which basically does the same thing, except doing memcmp for detecting the edid change. Is it only Intel specific change? As we could just add this modification to existing helper function or add another helper function to the drm (drm_probe_helper.c), so that it is also usable elsewhere..

I second Stanislav's proposal to add this feature as part of drm. This edid check could be part of existing drm_helper_hpd_irq_event() function. Other drivers might find this change useful.

...

/**

--  Best Regards,

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