Re: [PATCH] drm/msm/dsi: remove bpc > 8 entries from allow list

[Евгений Лепший <fekz115@gmail.com>]

Hi,

I have a concern regarding this patch. The Nothing Phone (1)
(sm7325-nothing-spacewar), which is already supported in mainline,
utilizes a panel with bpc=10 and bpp=8 (DSC) [1].

Currently, this configuration works properly. While I have encountered
minor graphical artifacts during brightness changes, the display
output is otherwise reliable across all supported refresh rates
(60/90/120 Hz).

Since this panel is already upstreamed, this patch might cause regressions.

[1] https://github.com/NothingOSS/android_kernel_devicetree_nothing_sm7325/blob/6f027f0440e3dce8a674d9cbd2f6ad944120e209/msm-extra/display-devicetree/display/dsi-panel-rm692e5-visionox-fhd-plus-120hz-cmd.dtsi#L483-L484

Best regards,
Eugene Lepshy

пт, 6 мар. 2026 г. в 21:47, Dmitry Baryshkov
<dmitry.baryshkov@oss.qualcomm.com>:
>
> On Fri, Mar 06, 2026 at 05:25:00PM +0800, Pengyu Luo wrote:
> > In upstream the msm, for bpc greater than 8 are not supported yet,
> > although the hardware block supports this. Remove them until we
> > support them.
> >
> > Fixes: b0e71c2637d1 ("drm/msm/dsi: Allow values of 10 and 12 for bits per component")
> > Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
>
> I hope Marijn, Danila or Eugeny can comment. The patch series with this
> patchset added 10 bpc panel and used it for one of the phones.
>
> > ---
> >  drivers/gpu/drm/msm/dsi/dsi_host.c | 7 ++-----
> >  1 file changed, 2 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > index e8e83ee61e..b60b26ddb0 100644
> > --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> > +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > @@ -1824,12 +1824,9 @@ static int dsi_populate_dsc_params(struct msm_dsi_host *msm_host, struct drm_dsc
> >
> >       switch (dsc->bits_per_component) {
> >       case 8:
> > -     case 10:
> > -     case 12:
> >               /*
> > -              * Only 8, 10, and 12 bpc are supported for DSC 1.1 block.
> > -              * If additional bpc values need to be supported, update
> > -              * this quard with the appropriate DSC version verification.
> > +              * In the upstream msm, only 8 bpc is supported for DSC 1.1/1.2
> > +              * block.
> >                */
> >               break;
> >       default:
> > --
> > 2.53.0
> >
>
> --
> With best wishes
> Dmitry