[PATCH] drm/vkms: add wait_for_vblanks in atomic_commit_tail

[Sidong Yang]

there is an error when igt test is run continuously. vkms_atomic_commit_tail()
need to call drm_atomic_helper_wait_for_vblanks() for give up ownership of
vblank events. without this code, next atomic commit will not enable vblank
and raise timeout error.

Signed-off-by: Sidong Yang <realwakka at gmail.com>
---
 drivers/gpu/drm/vkms/vkms_drv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 1e8b2169d834..10b9be67a068 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -93,6 +93,8 @@ static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
 		flush_work(&vkms_state->composer_work);
 	}
 
+	drm_atomic_helper_wait_for_vblanks(dev, old_state);
+
 	drm_atomic_helper_cleanup_planes(dev, old_state);
 }
 
-- 
2.17.1