From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Date: Fri, 14 Jul 2017 01:26:52 +0300
Subject: drm: rcar-du: Wait for flip completion instead of vblank in commit
 tail
Git-commit: d6160246f651b7cbd370408248f95c3bea8c24ed
Patch-mainline: v4.14-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Page flips can take more than one vertical blanking to complete if
arming the page flips races with the vertical blanking interrupt.
Waiting for one vblank to complete the atomic commit in the commit tail
handler is thus incorrect, and can lead to framebuffers being released
while still being scanned out.

Fix this by waiting for flip completion instead, using the
drm_atomic_helper_wait_for_flip_done() helper.

Fixes: 0d230422d256 ("drm: rcar-du: Register a completion callback with VSP1")
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_kms.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
@@ -262,7 +262,7 @@ static void rcar_du_atomic_commit_tail(s
 	drm_atomic_helper_commit_modeset_enables(dev, old_state);
 
 	drm_atomic_helper_commit_hw_done(old_state);
-	drm_atomic_helper_wait_for_vblanks(dev, old_state);
+	drm_atomic_helper_wait_for_flip_done(dev, old_state);
 
 	drm_atomic_helper_cleanup_planes(dev, old_state);
 }