linux-kernel - Re: [PATCH v2 08/14] drm/msm/dpu: update mixer number info earlier

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Message-ID: <CAA8EJpprO9pZ7bRf5HDA7-8UYKn5RiK2Yg9eW1NTYSEAE8ZDFw@mail.gmail.com>
Date: Fri, 11 Oct 2024 10:06:41 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Jun Nie <jun.nie@...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>, linux-arm-msm@...r.kernel.org, 
	dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 08/14] drm/msm/dpu: update mixer number info earlier

On Fri, 11 Oct 2024 at 09:30, Jun Nie <jun.nie@...aro.org> wrote:
>
> Dmitry Baryshkov <dmitry.baryshkov@...aro.org> 于2024年10月10日周四 21:12写道：
> >
> > On Wed, Oct 09, 2024 at 04:50:21PM GMT, Jun Nie wrote:
> > > Update mixer number info earlier so that the plane nopipe check
> > > can have the info to clip the plane. Otherwise, the first nonpipe
> > > check will have mixer number as 0 and plane is not checked.
> > >
> > > Signed-off-by: Jun Nie <jun.nie@...aro.org>
> > > ---
> > >  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 11 ++++++++++-
> > >  1 file changed, 10 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > index dfe282c607933..68655c8817bf8 100644
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > @@ -638,6 +638,7 @@ static int dpu_encoder_virt_atomic_check(
> > >       struct dpu_global_state *global_state;
> > >       struct drm_framebuffer *fb;
> > >       struct drm_dsc_config *dsc;
> > > +     struct dpu_crtc_state *cstate;
> > >       int ret = 0;
> > >
> > >       if (!drm_enc || !crtc_state || !conn_state) {
> > > @@ -662,6 +663,8 @@ static int dpu_encoder_virt_atomic_check(
> > >       dsc = dpu_encoder_get_dsc_config(drm_enc);
> > >
> > >       topology = dpu_encoder_get_topology(dpu_enc, dpu_kms, adj_mode, crtc_state, dsc);
> > > +     cstate = to_dpu_crtc_state(crtc_state);
> > > +     cstate->num_mixers = topology.num_lm;
> > >
> > >       /*
> > >        * Use CDM only for writeback or DP at the moment as other interfaces cannot handle it.
> > > @@ -1170,7 +1173,13 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
> > >       }
> > >
> > >       cstate->num_dscs = num_dsc;
> > > -     cstate->num_mixers = num_lm;
> > > +     if (cstate->num_mixers != num_lm) {
> > > +             if (!cstate->num_mixers)
> > > +                     DPU_ERROR_ENC(dpu_enc,
> > > +                                   "mixer number %d is not as expected %d\n",
> > > +                                   num_lm, cstate->num_mixers);
> > > +             cstate->num_mixers = num_lm;
> > > +     }
> >
> > Is it a possible case or just defensive coding?
>
> The value is initialized beforehand only in virtual plane case. So we
> still need this
> for non virtual plane case.

It looks better if it's handled in the non-virtual code instead.

-- 
With best wishes
Dmitry