linux-kernel - [PATCH v2] drm/msm/dpu: make "vblank timeout" more useful

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Message-Id: <20240208-fd-dpu-debug-timeout-v2-1-9f907f1bdd87@linaro.org>
Date: Thu, 08 Feb 2024 16:50:27 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Rob Clark <robdclark@...il.com>, 
 Abhinav Kumar <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>, 
 Marijn Suijten <marijn.suijten@...ainline.org>, 
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
 freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] drm/msm/dpu: make "vblank timeout" more useful

We have several reports of vblank timeout messages. However after some
debugging it was found that there might be different causes to that.
To allow us to identify the DPU block that gets stuck, include the
actual CTL_FLUSH value into the timeout message and trigger the devcore
snapshot capture.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
Changes in v2:
- Added a call to msm_disp_snapshot_state() to trigger devcore dump
  (Abhinav)
- Link to v1: https://lore.kernel.org/r/20240106-fd-dpu-debug-timeout-v1-1-6d9762884641@linaro.org
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 3 ++-
 1 file changed, 2 insertions(+), 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 d0f56c5c4cce..a8d6165b3c0a 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
@@ -489,7 +489,8 @@ static int dpu_encoder_phys_vid_wait_for_commit_done(
 		(hw_ctl->ops.get_flush_register(hw_ctl) == 0),
 		msecs_to_jiffies(50));
 	if (ret <= 0) {
-		DPU_ERROR("vblank timeout\n");
+		DPU_ERROR("vblank timeout: %x\n", hw_ctl->ops.get_flush_register(hw_ctl));
+		msm_disp_snapshot_state(phys_enc->parent->dev);
 		return -ETIMEDOUT;
 	}
 

---
base-commit: 39676dfe52331dba909c617f213fdb21015c8d10
change-id: 20240106-fd-dpu-debug-timeout-e917f0bc8063

Best regards,
-- 
Dmitry Baryshkov <dmitry.baryshkov@...aro.org>