Re: [PATCH v3 6/8] drm/msm/dpu: add support for MDP_TOP blackhole

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On 04/11/2022 16:58, Konrad Dybcio wrote:
> On 04/11/2022 14:03, Dmitry Baryshkov wrote:
> > On sm8450 a register block was removed from MDP TOP. Accessing it during
> > snapshotting results in NoC errors / immediate reboot. Skip accessing
> > these registers during snapshot.
>
> Must have been fun to debug..
>
>
> > Tested-by: Vinod Koul <vkoul@xxxxxxxxxx>
> > Reviewed-by: Vinod Koul <vkoul@xxxxxxxxxx>
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h |  1 +
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c        | 11 +++++++++--
> >   2 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h 
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> > index 38aa38ab1568..4730f8268f2a 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> > @@ -92,6 +92,7 @@ enum {
> >       DPU_MDP_UBWC_1_0,
> >       DPU_MDP_UBWC_1_5,
> >       DPU_MDP_AUDIO_SELECT,
> > +    DPU_MDP_PERIPH_0_REMOVED,
> >       DPU_MDP_MAX
> >   };
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c 
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > index f3660cd14f4f..95d8765c1c53 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > @@ -927,8 +927,15 @@ static void dpu_kms_mdp_snapshot(struct 
> > msm_disp_state *disp_state, struct msm_k
> >           msm_disp_snapshot_add_block(disp_state, cat->wb[i].len,
> >                   dpu_kms->mmio + cat->wb[i].base, "wb_%d", i);
> > -    msm_disp_snapshot_add_block(disp_state, cat->mdp[0].len,
> > -            dpu_kms->mmio + cat->mdp[0].base, "top");
> > +    if (dpu_kms->hw_mdp->caps->features & 
> > BIT(DPU_MDP_PERIPH_0_REMOVED)) {
> > +        msm_disp_snapshot_add_block(disp_state, 0x380,
> > +                dpu_kms->mmio + cat->mdp[0].base, "top");
> > +        msm_disp_snapshot_add_block(disp_state, cat->mdp[0].len - 0x3a8,
> > +                dpu_kms->mmio + cat->mdp[0].base + 0x3a8, "top_2");
>
> Are these values expected to stay the same on different new-gen SoCs? 
> Maybe it would
>
> be worth making it dynamic.

I do not want to overcomplicate this. Let's make it dynamic once there 
is need for that. For now I expect this will be static.

> Konrad
>
> > +    } else {
> > +        msm_disp_snapshot_add_block(disp_state, cat->mdp[0].len,
> > +                dpu_kms->mmio + cat->mdp[0].base, "top");
> > +    }
> >       pm_runtime_put_sync(&dpu_kms->pdev->dev);
> >   }

--
With best wishes
Dmitry