linux-kernel - Re: [PATCH 07/21] drm/msm/dpu: Support dynamic DSC number

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Message-ID: <CABymUCMCjYfXBOqXcLGZvH6CxU7Z_Qq1kKioZGC8PCORjtJM8Q@mail.gmail.com>
Date: Tue, 3 Sep 2024 15:48:36 +0800
From: Jun Nie <jun.nie@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Rob Clark <robdclark@...il.com>, Abhinav Kumar <quic_abhinavk@...cinc.com>, 
	Sean Paul <sean@...rly.run>, Marijn Suijten <marijn.suijten@...ainline.org>, 
	David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, linux-arm-msm@...r.kernel.org, 
	dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/21] drm/msm/dpu: Support dynamic DSC number

Dmitry Baryshkov <dmitry.baryshkov@...aro.org> 于2024年8月29日周四 19:10写道：
>
> On Thu, 29 Aug 2024 at 13:20, Jun Nie <jun.nie@...aro.org> wrote:
> >
> > Do not assume DSC number as 2. Because there are 4 DSC in
> > quad pipe case.
>
> Please expand the commit message. You prefer brevity, but your
> comments lack clarifications.

Is below message OK?

Current DSC number is fixed to 2 for any DSC usage case. While there are
more usage case that involve different number of DSC engine, such 4 in
quad-pipe case with bonded-DSI scenario. So retrieve the real number with
this change.

>
> >
> > Signed-off-by: Jun Nie <jun.nie@...aro.org>
> > ---
> >  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 4 ++--
> >  1 file changed, 2 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 6bdd9c21ff3ed..05b203be2a9bc 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > @@ -553,9 +553,9 @@ bool dpu_encoder_use_dsc_merge(struct drm_encoder *drm_enc)
> >                 if (dpu_enc->phys_encs[i])
> >                         intf_count++;
> >
> > -       /* See dpu_encoder_get_topology, we only support 2:2:1 topology */
> > +       /* DSC and mixer are mapped 1:1, so reuse the mixer number */
>
> Why? DSCmerge is a valid topology even if it is not supported yet.

DSC merge is already supported in 2:2:1 topology without this patch
set. This change
is to get real DSC number in 4:4:2 topology, so that DSC merge can be
enabled for the
case.

>
> >         if (dpu_enc->dsc)
> > -               num_dsc = 2;
> > +               num_dsc = dpu_crtc_get_lm_num(drm_enc->crtc->state);
> >
> >         return (num_dsc > 0) && (num_dsc > intf_count);
> >  }
> >
> > --
> > 2.34.1
> >
>
>
> --
> With best wishes
> Dmitry