Messages in this thread | | | Date | Wed, 14 Feb 2024 12:35:58 -0800 | Subject | Re: [PATCH v2] drm/msm/dpu: make "vblank timeout" more useful | From | Abhinav Kumar <> |
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On 2/14/2024 11:20 AM, Dmitry Baryshkov wrote: > On Wed, 14 Feb 2024 at 20:02, Abhinav Kumar <quic_abhinavk@quicinc.com> wrote: >> >> >> >> On 2/8/2024 6:50 AM, Dmitry Baryshkov wrote: >>> 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@linaro.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); >> >> >> There is no rate limiting in this piece of code unfortunately. So this >> will flood the number of snapshots. > > Well... Yes and no. The devcoredump will destroy other snapshots if > there is a pending one. So only the console will be flooded and only > in case when MSM_DISP_SNAPSHOT_DUMP_IN_CONSOLE is enabled. >
Yes, true but at the same time this makes it hard to capture a good dump as potentially every vblank you could timeout so this destroy/create cycle wont end.
>> >> Short-term solution is you can go with a vblank_timeout_cnt and reset it >> in the enable() like other similar error counters. >> >> long-term solution is we need to centralize these error locations to one >> single dpu_encoder_error_handler() with a single counter and the error >> handler will print out the error code along with the snapshot instead of >> the snapshot being called from all over the place. >> >> >> >>> return -ETIMEDOUT; >>> } >>> >>> >>> --- >>> base-commit: 39676dfe52331dba909c617f213fdb21015c8d10 >>> change-id: 20240106-fd-dpu-debug-timeout-e917f0bc8063 >>> >>> Best regards, > > >
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