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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Wed, 3 Apr 2024 18:00:36 +0300
Message-ID: <CAA8EJpo_TXTsuK6XsLx_3aFTXHjoe6FRRqOjcN6zd-FdAXZQAg@mail.gmail.com>
Subject: Re: [PATCH v3 1/6] drm/msm/dpu: fix video mode DSC for DSI
To: Jun Nie <jun.nie@linaro.org>
Cc: Rob Clark <robdclark@gmail.com>, Abhinav Kumar <quic_abhinavk@quicinc.com>, 
	Sean Paul <sean@poorly.run>, Marijn Suijten <marijn.suijten@somainline.org>, 
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, 
	Jessica Zhang <quic_jesszhan@quicinc.com>, Vinod Koul <vkoul@kernel.org>, 
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, 
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org, 
	Jonathan Marek <jonathan@marek.ca>
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On Wed, 3 Apr 2024 at 17:44, Jun Nie <jun.nie@linaro.org> wrote:
>
> Dmitry Baryshkov <dmitry.baryshkov@linaro.org> =E4=BA=8E2024=E5=B9=B44=E6=
=9C=883=E6=97=A5=E5=91=A8=E4=B8=89 17:57=E5=86=99=E9=81=93=EF=BC=9A
> >
> > On Wed, 3 Apr 2024 at 12:11, Jun Nie <jun.nie@linaro.org> wrote:
> > >
> > > From: Jonathan Marek <jonathan@marek.ca>
> > >
> > > Add necessary DPU timing and control changes for DSC to work with DSI
> > > video mode.
> > >
> > > Signed-off-by: Jonathan Marek <jonathan@marek.ca>
> > > Signed-off-by: Jun Nie <jun.nie@linaro.org>
> > > ---
> > >  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 9 +++++++++
> > >  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c          | 8 ++++++++
> > >  2 files changed, 17 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c b/d=
rivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> > > index d9e7dbf0499c..c7b009a60b63 100644
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> > > @@ -115,6 +115,15 @@ static void drm_mode_to_intf_timing_params(
> > >                 timing->h_front_porch =3D timing->h_front_porch >> 1;
> > >                 timing->hsync_pulse_width =3D timing->hsync_pulse_wid=
th >> 1;
> > >         }
> > > +
> > > +       /*
> > > +        * for DSI, if compression is enabled, then divide the horizo=
nal active
> > > +        * timing parameters by compression ratio.
> > > +        */
> > > +       if (phys_enc->hw_intf->cap->type !=3D INTF_DP && timing->comp=
ression_en) {
> > > +               timing->width =3D timing->width / 3; /* XXX: don't as=
sume 3:1 compression ratio */
> > > +               timing->xres =3D timing->width;
> > > +       }
> > >  }
> > >
> > >  static u32 get_horizontal_total(const struct dpu_hw_intf_timing_para=
ms *timing)
> > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c b/drivers/gp=
u/drm/msm/disp/dpu1/dpu_hw_intf.c
> > > index 965692ef7892..079efb48db05 100644
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> > > @@ -167,6 +167,14 @@ static void dpu_hw_intf_setup_timing_engine(stru=
ct dpu_hw_intf *ctx,
> > >                 intf_cfg2 |=3D INTF_CFG2_DATABUS_WIDEN;
> > >
> > >         data_width =3D p->width;
> > > +       if (p->wide_bus_en && !dp_intf)
> > > +               data_width =3D p->width >> 1;
> >
> > How is wide_bus relevant to the DSC case?
> > Is there a need for the Fixes tag?
>
> 48bit bus width should be used when DSC is enabled. Without the
> widebus configuration,
> a lot dsi error happens as below in DSC case.
> [  206.275992] dsi_err_worker: status=3D4

Still, separate patch please.

>
> For the Fixes tag, the previous patch mentioned to enable the widebus
> mode for any DSC case. So it is fair to add the tag.

Yes, please.

> >
> > > +
> > > +       if (p->compression_en)
> > > +               intf_cfg2 |=3D INTF_CFG2_DCE_DATA_COMPRESS;
> > > +
> > > +       if (p->compression_en && dp_intf)
> > > +               DPU_ERROR("missing adjustments for DSC+DP\n");
> > >
> > >         hsync_data_start_x =3D hsync_start_x;
> > >         hsync_data_end_x =3D  hsync_start_x + data_width - 1;
> > >
> > > --
> > > 2.34.1
> > >
> >
> >
> > --
> > With best wishes
> > Dmitry


--=20
With best wishes
Dmitry