Automatically try re-enabling TearFree after a flip failed

Specifically, after both the page flip and vblank ioctls failed, but
then the vblank ioctl started working again. This can happen
intermittently e.g. when hotplugging a DP display. Previously, TearFree
would stay disabled in that case until a modeset was triggered somehow.

Bugzilla: https://bugs.freedesktop.org/103791
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 71 insertions, 11 deletions

diff --git a/src/amdgpu_kms.c b/src/amdgpu_kms.c
index 44a3c8a..506e5f7 100644
--- a/src/amdgpu_kms.c
+++ b/src/amdgpu_kms.c
@@ -748,15 +748,32 @@ amdgpu_prime_scanout_update(PixmapDirtyUpdatePtr dirty)
 
 	if (!drmmode_wait_vblank(xf86_crtc, DRM_VBLANK_RELATIVE | DRM_VBLANK_EVENT,
 				 1, drm_queue_seq, NULL, NULL)) {
-		xf86DrvMsg(scrn->scrnIndex, X_WARNING,
-			   "drmmode_wait_vblank failed for PRIME update: %s\n",
-			   strerror(errno));
+		if (!(drmmode_crtc->scanout_status & DRMMODE_SCANOUT_VBLANK_FAILED)) {
+			xf86DrvMsg(scrn->scrnIndex, X_WARNING,
+				   "drmmode_wait_vblank failed for PRIME update: %s\n",
+				   strerror(errno));
+			drmmode_crtc->scanout_status |= DRMMODE_SCANOUT_VBLANK_FAILED;
+		}
+
 		drmmode_crtc->drmmode->event_context.vblank_handler(pAMDGPUEnt->fd,
 								    0, 0, 0,
 								    (void*)drm_queue_seq);
 		drmmode_crtc->wait_flip_nesting_level++;
 		amdgpu_drm_queue_handle_deferred(xf86_crtc);
+		return;
+	}
+
+	if (drmmode_crtc->scanout_status ==
+	    (DRMMODE_SCANOUT_FLIP_FAILED | DRMMODE_SCANOUT_VBLANK_FAILED)) {
+		/* The page flip and vblank ioctls failed before, but the vblank
+		 * ioctl is working again, so we can try re-enabling TearFree
+		 */
+		xf86_crtc->funcs->set_mode_major(xf86_crtc, &xf86_crtc->mode,
+						 xf86_crtc->rotation,
+						 xf86_crtc->x, xf86_crtc->y);
 	}
+
+	drmmode_crtc->scanout_status &= ~DRMMODE_SCANOUT_VBLANK_FAILED;
 }
 
 static void
@@ -807,12 +824,22 @@ amdgpu_prime_scanout_flip(PixmapDirtyUpdatePtr ent)
 	if (drmmode_page_flip_target_relative(pAMDGPUEnt, drmmode_crtc,
 					      drmmode_crtc->flip_pending->handle,
 					      0, drm_queue_seq, 0) != 0) {
-		xf86DrvMsg(scrn->scrnIndex, X_WARNING, "flip queue failed in %s: %s\n",
-			   __func__, strerror(errno));
+		if (!(drmmode_crtc->scanout_status & DRMMODE_SCANOUT_FLIP_FAILED)) {
+			xf86DrvMsg(scrn->scrnIndex, X_WARNING,
+				   "flip queue failed in %s: %s, TearFree inactive\n",
+				   __func__, strerror(errno));
+			drmmode_crtc->scanout_status |= DRMMODE_SCANOUT_FLIP_FAILED;
+		}
+
 		amdgpu_drm_abort_entry(drm_queue_seq);
 		return;
 	}
 
+	if (drmmode_crtc->scanout_status & DRMMODE_SCANOUT_FLIP_FAILED) {
+		xf86DrvMsg(scrn->scrnIndex, X_INFO, "TearFree active again\n");
+		drmmode_crtc->scanout_status &= ~DRMMODE_SCANOUT_FLIP_FAILED;
+	}
+
 	drmmode_crtc->scanout_id = scanout_id;
 	drmmode_crtc->scanout_update_pending = drm_queue_seq;
 }
@@ -1029,15 +1056,32 @@ amdgpu_scanout_update(xf86CrtcPtr xf86_crtc)
 
 	if (!drmmode_wait_vblank(xf86_crtc, DRM_VBLANK_RELATIVE | DRM_VBLANK_EVENT,
 				 1, drm_queue_seq, NULL, NULL)) {
-		xf86DrvMsg(scrn->scrnIndex, X_WARNING,
-			   "drmmode_wait_vblank failed for scanout update: %s\n",
-			   strerror(errno));
+		if (!(drmmode_crtc->scanout_status & DRMMODE_SCANOUT_VBLANK_FAILED)) {
+			xf86DrvMsg(scrn->scrnIndex, X_WARNING,
+				   "drmmode_wait_vblank failed for scanout update: %s\n",
+				   strerror(errno));
+			drmmode_crtc->scanout_status |= DRMMODE_SCANOUT_VBLANK_FAILED;
+		}
+
 		drmmode_crtc->drmmode->event_context.vblank_handler(pAMDGPUEnt->fd,
 								    0, 0, 0,
 								    (void*)drm_queue_seq);
 		drmmode_crtc->wait_flip_nesting_level++;
 		amdgpu_drm_queue_handle_deferred(xf86_crtc);
+		return;
+	}
+
+	if (drmmode_crtc->scanout_status ==
+	    (DRMMODE_SCANOUT_FLIP_FAILED | DRMMODE_SCANOUT_VBLANK_FAILED)) {
+		/* The page flip and vblank ioctls failed before, but the vblank
+		 * ioctl is working again, so we can try re-enabling TearFree
+		 */
+		xf86_crtc->funcs->set_mode_major(xf86_crtc, &xf86_crtc->mode,
+						 xf86_crtc->rotation,
+						 xf86_crtc->x, xf86_crtc->y);
 	}
+
+	drmmode_crtc->scanout_status &= ~DRMMODE_SCANOUT_VBLANK_FAILED;
 }
 
 static void
@@ -1089,9 +1133,13 @@ amdgpu_scanout_flip(ScreenPtr pScreen, AMDGPUInfoPtr info,
 	if (drmmode_page_flip_target_relative(pAMDGPUEnt, drmmode_crtc,
 					      drmmode_crtc->flip_pending->handle,
 					      0, drm_queue_seq, 0) != 0) {
-		xf86DrvMsg(scrn->scrnIndex, X_WARNING, "flip queue failed in %s: %s, "
-			   "TearFree inactive until next modeset\n",
-			   __func__, strerror(errno));
+		if (!(drmmode_crtc->scanout_status & DRMMODE_SCANOUT_FLIP_FAILED)) {
+			xf86DrvMsg(scrn->scrnIndex, X_WARNING,
+				   "flip queue failed in %s: %s, TearFree inactive\n",
+				   __func__, strerror(errno));
+			drmmode_crtc->scanout_status |= DRMMODE_SCANOUT_FLIP_FAILED;
+		}
+
 		amdgpu_drm_abort_entry(drm_queue_seq);
 		RegionCopy(DamageRegion(drmmode_crtc->scanout_damage),
 			   &drmmode_crtc->scanout_last_region);
@@ -1103,6 +1151,11 @@ amdgpu_scanout_flip(ScreenPtr pScreen, AMDGPUInfoPtr info,
 		return;
 	}
 
+	if (drmmode_crtc->scanout_status & DRMMODE_SCANOUT_FLIP_FAILED) {
+		xf86DrvMsg(scrn->scrnIndex, X_INFO, "TearFree active again\n");
+		drmmode_crtc->scanout_status &= ~DRMMODE_SCANOUT_FLIP_FAILED;
+	}
+
 	drmmode_crtc->scanout_id = scanout_id;
 	drmmode_crtc->scanout_update_pending = drm_queue_seq;
 }
diff --git a/src/drmmode_display.h b/src/drmmode_display.h
index b2b16df..aab330c 100644
--- a/src/drmmode_display.h
+++ b/src/drmmode_display.h
@@ -91,6 +91,12 @@ struct drmmode_fb {
 	uint32_t handle;
 };
 
+enum drmmode_scanout_status {
+	DRMMODE_SCANOUT_OK,
+	DRMMODE_SCANOUT_FLIP_FAILED = 1u << 0,
+	DRMMODE_SCANOUT_VBLANK_FAILED = 1u << 1,
+};
+
 struct drmmode_scanout {
 	struct amdgpu_buffer *bo;
 	PixmapPtr pixmap;
@@ -110,6 +116,7 @@ typedef struct {
 	unsigned scanout_id;
 	uintptr_t scanout_update_pending;
 	Bool tear_free;
+	enum drmmode_scanout_status scanout_status;
 	Bool vrr_enabled;
 
 	PixmapPtr prime_scanout_pixmap;