[PATCH] drm/xe/display: Avoid dig_port work during suspend

[Dibin Moolakadan Subrahmanian]

 It has been observed that during `xe_display_pm_suspend()` execution,
 an HPD interrupt can still be triggered, resulting in `dig_port_work`
 being scheduled. The issue arises when this work executes after
 `xe_display_pm_suspend_late()`, by which time the display is fully
 suspended.

 This can lead to errors such as "DC state mismatch", as the dig_port
 work accesses display resources that are no longer available or
 powered.

 To address this, introduce a new `ignore_dig_port` flag in the
 hotplug in structure. This flag is checked in the interrupt handler to
 prevent queuing of `dig_port_work` while the system is mid-suspend.
 This behavior is consistent with the existing approach of suppressing
 hotplug_work during suspend.

Signed-off-by: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian at intel.com>
---
 .../gpu/drm/i915/display/intel_display_core.h |  3 +++
 drivers/gpu/drm/i915/display/intel_hotplug.c  | 22 ++++++++++++++++++-
 drivers/gpu/drm/i915/display/intel_hotplug.h  |  2 ++
 drivers/gpu/drm/xe/display/xe_display.c       |  4 ++++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h
index 8c226406c5cd..376682c53798 100644
--- a/drivers/gpu/drm/i915/display/intel_display_core.h
+++ b/drivers/gpu/drm/i915/display/intel_display_core.h
@@ -209,6 +209,9 @@ struct intel_hotplug {
 	 * cue to ignore the long HPDs and can be set / unset using debugfs.
 	 */
 	bool ignore_long_hpd;
+
+	/* Flag to ignore dig_port work , used in suspend*/
+	bool ignore_dig_port;
 };
 
 struct intel_vbt_data {
diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
index 265aa97fcc75..b2891b7c3205 100644
--- a/drivers/gpu/drm/i915/display/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
@@ -223,6 +223,26 @@ queue_detection_work(struct intel_display *display, struct work_struct *work)
 	return queue_work(display->wq.unordered, work);
 }
 
+void intel_hpd_ignore_dig_port_work(struct intel_display *display, bool value)
+{
+	if (!HAS_DISPLAY(display))
+		return;
+
+	spin_lock_irq(&display->irq.lock);
+	display->hotplug.ignore_dig_port = value;
+	spin_unlock_irq(&display->irq.lock);
+}
+
+bool intel_hpd_can_queue_dig_port(struct intel_display *display)
+{
+	if (!HAS_DISPLAY(display))
+		return FALSE;
+
+	lockdep_assert_held(&display->irq.lock);
+
+	return !display->hotplug.ignore_dig_port;
+}
+
 static void
 intel_hpd_irq_storm_switch_to_polling(struct intel_display *display)
 {
@@ -691,7 +711,7 @@ void intel_hpd_irq_handler(struct intel_display *display,
 	 * queue for otherwise the flush_work in the pageflip code will
 	 * deadlock.
 	 */
-	if (queue_dig)
+	if (queue_dig && intel_hpd_can_queue_dig_port(display))
 		queue_work(display->hotplug.dp_wq, &display->hotplug.dig_port_work);
 	if (queue_hp)
 		queue_delayed_detection_work(display,
diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.h b/drivers/gpu/drm/i915/display/intel_hotplug.h
index edc41c9d3d65..9dc40ec7074c 100644
--- a/drivers/gpu/drm/i915/display/intel_hotplug.h
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.h
@@ -34,5 +34,7 @@ void intel_hpd_debugfs_register(struct intel_display *display);
 void intel_hpd_enable_detection_work(struct intel_display *display);
 void intel_hpd_disable_detection_work(struct intel_display *display);
 bool intel_hpd_schedule_detection(struct intel_display *display);
+void intel_hpd_ignore_dig_port_work(struct intel_display *display, bool value);
+bool intel_hpd_can_queue_dig_port(struct intel_display *display);
 
 #endif /* __INTEL_HOTPLUG_H__ */
diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
index e2e0771cf274..2db71bd07c9f 100644
--- a/drivers/gpu/drm/xe/display/xe_display.c
+++ b/drivers/gpu/drm/xe/display/xe_display.c
@@ -342,6 +342,8 @@ void xe_display_pm_suspend(struct xe_device *xe)
 
 	intel_hpd_cancel_work(display);
 
+	intel_hpd_ignore_dig_port_work(display, 1);
+
 	if (has_display(xe)) {
 		intel_display_driver_suspend_access(display);
 		intel_encoder_suspend_all(display);
@@ -469,6 +471,8 @@ void xe_display_pm_resume(struct xe_device *xe)
 	if (has_display(xe))
 		intel_display_driver_resume_access(display);
 
+	intel_hpd_ignore_dig_port_work(display, 0);
+
 	intel_hpd_init(display);
 
 	if (has_display(xe)) {
-- 
2.43.0