Re: [PATCH v2 09/11] drm/msm/disp/dpu1: Add support for DSC in topology

[Dmitry Baryshkov]

On 14/10/2021 17:13, Dmitry Baryshkov wrote:
> On 07/10/2021 10:08, Vinod Koul wrote:
> > For DSC to work we typically need a 2,2,1 configuration. This should
> > suffice for resolutions upto 4k. For more resolutions like 8k this won't
> > work.
> >
> > Also, it is better to use 2 LMs and DSC instances as half width results
> > in lesser power consumption as compared to single LM, DSC at full width.
> >
> > The panel has been tested only with 2,2,1 configuration, so for
> > now we blindly create 2,2,1 topology when DSC is enabled
> >
> > Co-developed-by: Abhinav Kumar <abhinavk@xxxxxxxxxxxxxx>
> > Signed-off-by: Abhinav Kumar <abhinavk@xxxxxxxxxxxxxx>
> > Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
> > ---
> > Changes since
> > RFC:
> >   - Add more details in changelog
> >
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 16 ++++++++++++++++
> >   1 file changed, 16 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c 
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > index aac51c1bdf94..70f57a071165 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > @@ -538,6 +538,8 @@ static struct msm_display_topology 
> > dpu_encoder_get_topology(
> >               struct drm_display_mode *mode)
> >   {
> >       struct msm_display_topology topology = {0};
> > +    struct drm_encoder *drm_enc;
> > +    struct msm_drm_private *priv;
> >       int i, intf_count = 0;
> >       for (i = 0; i < MAX_PHYS_ENCODERS_PER_VIRTUAL; i++)
> > @@ -572,8 +574,22 @@ static struct msm_display_topology 
> > dpu_encoder_get_topology(
> >       topology.num_enc = 0;
> >       topology.num_intf = intf_count;
> > +    drm_enc = &dpu_enc->base;
> > +    priv = drm_enc->dev->dev_private;
> > +    if (priv && priv->dsc) {
> > +        /* In case of Display Stream Compression DSC, we would use
> > +         * 2 encoders, 2 line mixers and 1 interface
> > +         * this is power optimal and can drive upto (including) 4k
> > +         * screens
> > +         */
> > +        topology.num_enc = 2;
> > +        topology.num_intf = 1;
> > +        topology.num_lm = 2;
>
> So, here you'd set the topology.num_rm.

I meant 'num_dsc', please excuse the typo.

> > +    }
> > +
> >       return topology;
> >   }
> > +
> >   static int dpu_encoder_virt_atomic_check(
> >           struct drm_encoder *drm_enc,
> >           struct drm_crtc_state *crtc_state,


--
With best wishes
Dmitry