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* [PATCH v4 1/2] drm: introduce KMS recovery mechanism
@ 2026-02-20 17:15 Hamza Mahfooz
  2026-02-20 17:15 ` [PATCH v4 2/2] drm/amd/display: add vendor specific reset Hamza Mahfooz
  2026-02-28 18:48 ` [PATCH v4 1/2] drm: introduce KMS recovery mechanism Shengyu Qu
  0 siblings, 2 replies; 7+ messages in thread
From: Hamza Mahfooz @ 2026-02-20 17:15 UTC (permalink / raw)
  To: dri-devel
  Cc: Michel Dänzer, Mario Limonciello, Hamza Mahfooz,
	Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, David Airlie, Simona Vetter,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Alex Hung,
	Aurabindo Pillai, Wayne Lin, Timur Kristóf, Ivan Lipski,
	Dominik Kaszewski, amd-gfx, linux-kernel

There should be a mechanism for drivers to respond to flip_done
timeouts. Since, as it stands it is possible for the display to stall
indefinitely, necessitating a hard reset. So, introduce a new mechanism
that tries various methods of recovery with increasing aggression, in
the following order:

1. Force a full modeset (have the compositor reprogram the state from
   scratch).
2. As a last resort, have the driver attempt a vendor specific reset
   (which they can do by reading the return value of
   drm_atomic_helper_wait_for_flip_done()).

Signed-off-by: Hamza Mahfooz <someguy@effective-light.com>
---
v2: new to the series
v3: get rid of page_flip_timeout() and have
    drm_atomic_helper_wait_for_flip_done() return a error.
v4: get rid of nested ret variable.
---
 drivers/gpu/drm/drm_atomic_helper.c | 47 ++++++++++++++++++++++++-----
 include/drm/drm_atomic_helper.h     |  4 +--
 include/drm/drm_device.h            | 24 +++++++++++++++
 3 files changed, 66 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 5840e9cc6f66..d905eb166225 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -42,6 +42,7 @@
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_panic.h>
 #include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
 #include <drm/drm_self_refresh_helper.h>
 #include <drm/drm_vblank.h>
 #include <drm/drm_writeback.h>
@@ -1864,30 +1865,62 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_vblanks);
  *
  * This requires that drivers use the nonblocking commit tracking support
  * initialized using drm_atomic_helper_setup_commit().
+ *
+ * Returns:
+ * -ETIMEDOUT to indicate that drivers can attempt a vendor reset, 0 otherwise.
  */
-void drm_atomic_helper_wait_for_flip_done(struct drm_device *dev,
-					  struct drm_atomic_state *state)
+int drm_atomic_helper_wait_for_flip_done(struct drm_device *dev,
+					 struct drm_atomic_state *state)
 {
 	struct drm_crtc *crtc;
+	int ret = 0;
 	int i;
 
 	for (i = 0; i < dev->mode_config.num_crtc; i++) {
 		struct drm_crtc_commit *commit = state->crtcs[i].commit;
-		int ret;
 
 		crtc = state->crtcs[i].ptr;
 
 		if (!crtc || !commit)
 			continue;
 
-		ret = wait_for_completion_timeout(&commit->flip_done, 10 * HZ);
-		if (ret == 0)
-			drm_err(dev, "[CRTC:%d:%s] flip_done timed out\n",
-				crtc->base.id, crtc->name);
+		if (!wait_for_completion_timeout(&commit->flip_done, 10 * HZ)) {
+			switch (dev->reset_phase) {
+			case DRM_KMS_RESET_NONE:
+				drm_err(dev, "[CRTC:%d:%s] flip_done timed out\n",
+					crtc->base.id, crtc->name);
+				dev->reset_phase = DRM_KMS_RESET_FORCE_MODESET;
+				drm_kms_helper_hotplug_event(dev);
+				break;
+			case DRM_KMS_RESET_FORCE_MODESET:
+				drm_err(dev, "[CRTC:%d:%s] force full modeset failed\n",
+					crtc->base.id, crtc->name);
+				dev->reset_phase = DRM_KMS_RESET_VENDOR;
+				ret = -ETIMEDOUT;
+				break;
+			case DRM_KMS_RESET_VENDOR:
+				drm_err(dev, "[CRTC:%d:%s] KMS recovery failed!\n",
+					crtc->base.id, crtc->name);
+				dev->reset_phase = DRM_KMS_RESET_GIVE_UP;
+				break;
+			default:
+				break;
+			}
+
+			goto exit;
+		}
+	}
+
+	if (dev->reset_phase) {
+		drm_info(dev, "KMS recovery succeeded!\n");
+		dev->reset_phase = DRM_KMS_RESET_NONE;
 	}
 
+exit:
 	if (state->fake_commit)
 		complete_all(&state->fake_commit->flip_done);
+
+	return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_wait_for_flip_done);
 
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 53382fe93537..298c8dff3993 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -79,8 +79,8 @@ int drm_atomic_helper_wait_for_fences(struct drm_device *dev,
 void drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
 					struct drm_atomic_state *old_state);
 
-void drm_atomic_helper_wait_for_flip_done(struct drm_device *dev,
-					  struct drm_atomic_state *old_state);
+int drm_atomic_helper_wait_for_flip_done(struct drm_device *dev,
+					 struct drm_atomic_state *old_state);
 
 void
 drm_atomic_helper_update_legacy_modeset_state(struct drm_device *dev,
diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
index bc78fb77cc27..1244d7527e7b 100644
--- a/include/drm/drm_device.h
+++ b/include/drm/drm_device.h
@@ -66,6 +66,23 @@ enum switch_power_state {
 	DRM_SWITCH_POWER_DYNAMIC_OFF = 3,
 };
 
+/**
+ * enum drm_kms_reset_phase - reset phase of drm device
+ */
+enum drm_kms_reset_phase {
+	/** @DRM_KMS_RESET_NONE: Not currently attempting recovery */
+	DRM_KMS_RESET_NONE,
+
+	/** @DRM_KMS_RESET_FORCE_MODESET: Force a full modeset */
+	DRM_KMS_RESET_FORCE_MODESET,
+
+	/** @DRM_KMS_RESET_VENDOR: Attempt a vendor reset */
+	DRM_KMS_RESET_VENDOR,
+
+	/** @DRM_KMS_RESET_GIVE_UP: All recovery methods failed */
+	DRM_KMS_RESET_GIVE_UP,
+};
+
 /**
  * struct drm_device - DRM device structure
  *
@@ -375,6 +392,13 @@ struct drm_device {
 	 * Root directory for debugfs files.
 	 */
 	struct dentry *debugfs_root;
+
+	/**
+	 * @reset_phase:
+	 *
+	 * Reset phase that the device is in.
+	 */
+	enum drm_kms_reset_phase reset_phase;
 };
 
 void drm_dev_set_dma_dev(struct drm_device *dev, struct device *dma_dev);
-- 
2.53.0


^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2026-02-28 18:48 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-02-20 17:15 [PATCH v4 1/2] drm: introduce KMS recovery mechanism Hamza Mahfooz
2026-02-20 17:15 ` [PATCH v4 2/2] drm/amd/display: add vendor specific reset Hamza Mahfooz
2026-02-20 17:37   ` Hamza Mahfooz
2026-02-22  1:32   ` kernel test robot
2026-02-23  9:34   ` Christian König
2026-02-27 20:58     ` Hamza Mahfooz
2026-02-28 18:48 ` [PATCH v4 1/2] drm: introduce KMS recovery mechanism Shengyu Qu

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