[PATCH] drm: rcar-du: Fix Kconfig dependency between RCAR_DU and RCAR_MIPI_DSI

[Geert Uytterhoeven]

 Hi Laurent,

On Mon, Nov 14, 2022 at 3:22 PM Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
> On Mon, Nov 14, 2022 at 10:05:58AM +0100, Geert Uytterhoeven wrote:
> > On Sun, Oct 2, 2022 at 12:06 AM Laurent Pinchart wrote:
> > > When the R-Car MIPI DSI driver was added, it was a standalone encoder
> > > driver without any dependency to or from the R-Car DU driver. Commit
> > > 957fe62d7d15 ("drm: rcar-du: Fix DSI enable & disable sequence") then
> > > added a direct call from the DU driver to the MIPI DSI driver, without
> > > updating Kconfig to take the new dependency into account. Fix it the
> > > same way that the LVDS encoder is handled.
> > >
> > > Fixes: 957fe62d7d15 ("drm: rcar-du: Fix DSI enable & disable sequence")
> > > Reported-by: kernel test robot <lkp at intel.com>
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> >
> > Thanks for your patch, which is now commit a830a15678593948
> > ("drm: rcar-du: Fix Kconfig dependency between RCAR_DU
> > and RCAR_MIPI_DSI") in v6.1-rc5.
> >
> > > --- a/drivers/gpu/drm/rcar-du/Kconfig
> > > +++ b/drivers/gpu/drm/rcar-du/Kconfig
> > > @@ -44,12 +44,17 @@ config DRM_RCAR_LVDS
> > >         select OF_FLATTREE
> > >         select OF_OVERLAY
> > >
> > > +config DRM_RCAR_USE_MIPI_DSI
> > > +       bool "R-Car DU MIPI DSI Encoder Support"
> > > +       depends on DRM_BRIDGE && OF
> > > +       default DRM_RCAR_DU
> >
> > This means this driver is now enabled by default on systems that do not
> > have the MIPI DSI Encoder (e.g. R-Car Gen2), and that we should probably
> > disable it explicitly in shmobile_defconfig.  Is that intentional?
>
> I don't think so, no. Would you like to send a patch ? If so, it should
> enable the option in relevant defconfig files.

You mean just drop the "default DRM_RCAR_DU" here?

I'm wondering if we can solve this in a consistent way.
Currently we have:

    config DRM_RCAR_USE_CMM default DRM_RCAR_DU
    config DRM_RCAR_DW_HDMI default n
    config DRM_RCAR_USE_LVDS default DRM_RCAR_DU
    config DRM_RCAR_MIPI_DSI default n
    config DRM_RCAR_VSP default y if ARM64

HDMI is only used on R-Car Gen3 parts
MIPI_DSI is only used on R-Car Gen4 parts
LVDS is used on R-Car Gen2 and Gen3 parts

Thoughts?

> > > +       help
> > > +         Enable support for the R-Car Display Unit embedded MIPI DSI encoders.
> > > +
> > >  config DRM_RCAR_MIPI_DSI
> > > -       tristate "R-Car DU MIPI DSI Encoder Support"
> > > -       depends on DRM && DRM_BRIDGE && OF
> > > +       def_tristate DRM_RCAR_DU
> > > +       depends on DRM_RCAR_USE_MIPI_DSI
> > >         select DRM_MIPI_DSI
> > > -       help
> > > -         Enable support for the R-Car Display Unit embedded MIPI DSI encoders.
> > >
> > >  config DRM_RCAR_VSP
> > >         bool "R-Car DU VSP Compositor Support" if ARM

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds