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

[Paloma Arellano <quic_parellan@xxxxxxxxxxx>]

On 11/27/2023 5:48 PM, Dmitry Baryshkov wrote:
> On Tue, 28 Nov 2023 at 03:12, Paloma Arellano <quic_parellan@xxxxxxxxxxx> 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@xxxxxxxxxxx>
> > ---
> >   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.

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