[PATCH 4.14 41/72] drm/msm: Grab a vblank reference when waiting for commit_done

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 3b712e43e3876b42b38321ecf790a1f5fe59c834 ]

Similar to the atomic helpers, we should enable vblank while we're
waiting for the commit to finish. DPU needs this, MDP5 seems to work
fine without it.

Reviewed-by: Abhinav Kumar <abhinavk@xxxxxxxxxxxxxx>
Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
Signed-off-by: Rob Clark <robdclark@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/msm/msm_atomic.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c
index 025d454163b0..8f77047a226d 100644
--- a/drivers/gpu/drm/msm/msm_atomic.c
+++ b/drivers/gpu/drm/msm/msm_atomic.c
@@ -93,7 +93,12 @@ static void msm_atomic_wait_for_commit_done(struct drm_device *dev,
 		if (!new_crtc_state->active)
 			continue;
 
+		if (drm_crtc_vblank_get(crtc))
+			continue;
+
 		kms->funcs->wait_for_crtc_commit_done(kms, crtc);
+
+		drm_crtc_vblank_put(crtc);
 	}
 }
 
-- 
2.19.1