[PATCH 4.19 130/313] drm/msm: dpu: Only check flush register against pending flushes

From: Greg Kroah-Hartman
Date: Mon Feb 11 2019 - 10:44:27 EST

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


[ Upstream commit 5f79e03b1f7c1b2cf0019ce6365fe5d52629813d ]

There exists a case where a flush of a plane/dma may have been triggered
& started from an async commit. If that plane/dma is subsequently disabled
by the next commit, the flush register will continue to hold the flush
bit for the disabled plane. Since the bit remains active,
pending_kickoff_cnt will never decrement and we'll miss frame_done

This patch limits the check of flush_register to include only those bits
which have been updated with the latest commit.

Changes in v2:
- None

Reviewed-by: Jeykumar Sankaran <jsanka@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/disp/dpu1/dpu_encoder_phys_vid.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
index 14fc7c2a6bb7..c9962a36b86b 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
@@ -331,7 +331,7 @@ static void dpu_encoder_phys_vid_vblank_irq(void *arg, int irq_idx)
if (hw_ctl && hw_ctl->ops.get_flush_register)
flush_register = hw_ctl->ops.get_flush_register(hw_ctl);

- if (flush_register == 0)
+ if (!(flush_register & hw_ctl->ops.get_pending_flush(hw_ctl)))
new_cnt = atomic_add_unless(&phys_enc->pending_kickoff_cnt,
-1, 0);
spin_unlock_irqrestore(phys_enc->enc_spinlock, lock_flags);