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

[Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>]

On 10/11/2022 21:19, Dmitry Baryshkov wrote:
> 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.
Let's roll with that.

Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>

Konrad
> > 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);
> > >   }