[PATCH] drm/msm/dpu: Capture dpu snapshot when frame_done_timer timeouts

[Dmitry Baryshkov]

On Tue, 28 Nov 2023 at 19:43, Paloma Arellano <quic_parellan at quicinc.com> wrote:
>
>
> On 11/27/2023 5:48 PM, Dmitry Baryshkov wrote:
> > On Tue, 28 Nov 2023 at 03:12, Paloma Arellano <quic_parellan at quicinc.com> wrote:
> >> Trigger a devcoredump to dump dpu registers and capture the drm atomic
> >> state when the frame_done_timer timeouts.
> >>
> >> Signed-off-by: Paloma Arellano <quic_parellan at quicinc.com>
> >> ---
> >>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 13 +++++++++++--
> >>   1 file changed, 11 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> index 1cf7ff6caff4..5cf7594feb5a 100644
> >> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> @@ -191,6 +191,7 @@ struct dpu_encoder_virt {
> >>          void *crtc_frame_event_cb_data;
> >>
> >>          atomic_t frame_done_timeout_ms;
> >> +       atomic_t frame_done_timeout_cnt;
> >>          struct timer_list frame_done_timer;
> >>
> >>          struct msm_display_info disp_info;
> >> @@ -1204,6 +1205,8 @@ static void dpu_encoder_virt_atomic_enable(struct drm_encoder *drm_enc,
> >>
> >>          dpu_enc->dsc = dpu_encoder_get_dsc_config(drm_enc);
> >>
> >> +       atomic_set(&dpu_enc->frame_done_timeout_cnt, 0);
> >> +
> >>          if (disp_info->intf_type == INTF_DP)
> >>                  dpu_enc->wide_bus_en = msm_dp_wide_bus_available(priv->dp[index]);
> >>          else if (disp_info->intf_type == INTF_DSI)
> >> @@ -2115,11 +2118,12 @@ static int _dpu_encoder_status_show(struct seq_file *s, void *data)
> >>          for (i = 0; i < dpu_enc->num_phys_encs; i++) {
> >>                  struct dpu_encoder_phys *phys = dpu_enc->phys_encs[i];
> >>
> >> -               seq_printf(s, "intf:%d  wb:%d  vsync:%8d     underrun:%8d    ",
> >> +               seq_printf(s, "intf:%d  wb:%d  vsync:%8d     underrun:%8d    frame_done_cnt:%d",
> >>                                  phys->hw_intf ? phys->hw_intf->idx - INTF_0 : -1,
> >>                                  phys->hw_wb ? phys->hw_wb->idx - WB_0 : -1,
> >>                                  atomic_read(&phys->vsync_cnt),
> >> -                               atomic_read(&phys->underrun_cnt));
> >> +                               atomic_read(&phys->underrun_cnt),
> >> +                               atomic_read(&dpu_enc->frame_done_timeout_cnt));
> >>
> >>                  seq_printf(s, "mode: %s\n", dpu_encoder_helper_get_intf_type(phys->intf_mode));
> >>          }
> >> @@ -2341,6 +2345,10 @@ static void dpu_encoder_frame_done_timeout(struct timer_list *t)
> >>
> >>          DPU_ERROR_ENC(dpu_enc, "frame done timeout\n");
> >>
> >> +       atomic_inc(&dpu_enc->frame_done_timeout_cnt);
> >> +       if (atomic_read(&dpu_enc->frame_done_timeout_cnt) == 1)
> >> +               msm_disp_snapshot_state(drm_enc->dev);
> > atomic_inc_and_test(), please
>
> Hi Dmitry,
>
> We only want to create a snapshot for the first instance in which the
> timer timeouts. atomic_int_and_test() increments the value and then
> returns whether it has a value of zero or not. FWIW I think I should
> change it to 'atomic_add_return(1, &dpu_enc->frame_done_timeout_cnt)' so
> that we can check only when this value equals one.

Works for me too.

I suggested atomic_inc_test() because then we can let devcoredump take
care of duplicate events.

>
> Thank you,
>
> Paloma
>
> >
> >> +
> >>          event = DPU_ENCODER_FRAME_EVENT_ERROR;
> >>          trace_dpu_enc_frame_done_timeout(DRMID(drm_enc), event);
> >>          dpu_enc->crtc_frame_event_cb(dpu_enc->crtc_frame_event_cb_data, event);
> >> @@ -2392,6 +2400,7 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
> >>                  goto fail;
> >>
> >>          atomic_set(&dpu_enc->frame_done_timeout_ms, 0);
> >> +       atomic_set(&dpu_enc->frame_done_timeout_cnt, 0);
> >>          timer_setup(&dpu_enc->frame_done_timer,
> >>                          dpu_encoder_frame_done_timeout, 0);
> >>
> >> --
> >> 2.41.0
> >>
> >



-- 
With best wishes
Dmitry