Re: [PATCH v2 04/11] drm/mediatek: Add OVL compatible name for MT8195

[AngeloGioacchino Del Regno]

Il 11/10/23 11:38, Shawn Sung (宋孝謙) ha scritto:
> Hi, Angelo and CK,
>
> On Mon, 2023-09-18 at 11:21 +0200, AngeloGioacchino Del Regno wrote:
> > Il 18/09/23 11:09, CK Hu (胡俊光) ha scritto:
> > > On Mon, 2023-09-18 at 16:42 +0800, Hsiao Chien Sung wrote:
> > > > Add OVL compatible name for MT8195.
> > >
> > > Reviewed-by: CK Hu <ck.hu@xxxxxxxxxxxx>
> > >
> > > but it's weird to put this patch into IGT series. Without this
> > > patch,
> > > mt8195 drm driver does not work not only IGT.
> >
> > The driver does work because the devicetree node declares two
> > compatibles,
> > "mediatek,mt8195-disp-ovl", "mediatek,mt8183-disp-ovl" where the
> > second
> > compatible is matched in mtk_drm_drv, and the first is matched in
> > mtk_disp_ovl
> > as both are platform_driver.
> >
> > This commit is not necessary, even... :-)
> >
> > Regards,
> > Angelo
> >
> > > Regards,
> > > CK
> > >
> > > > Signed-off-by: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>
> > > > ---
> > > >    drivers/gpu/drm/mediatek/mtk_drm_drv.c | 2 ++
> > > >    1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > > > b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > > > index 93552d76b6e7..7759a06e5c0e 100644
> > > > --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > > > +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> > > > @@ -715,6 +715,8 @@ static const struct of_device_id
> > > > mtk_ddp_comp_dt_ids[] = {
> > > >    	  .data = (void *)MTK_DISP_OVL },
> > > >    	{ .compatible = "mediatek,mt8192-disp-ovl",
> > > >    	  .data = (void *)MTK_DISP_OVL },
> > > > +	{ .compatible = "mediatek,mt8195-disp-ovl",
> > > > +	  .data = (void *)MTK_DISP_OVL },
> > > >    	{ .compatible = "mediatek,mt8183-disp-ovl-2l",
> > > >    	  .data = (void *)MTK_DISP_OVL_2L },
> > > >    	{ .compatible = "mediatek,mt8192-disp-ovl-2l",
>
> Please refer to c6aa5f1fb505. This is the main reason why we have to
> use MT8195 instead of MT8183/MT8192. Most of the formats required by
> IGT is not supported.
>
> Without this commit, DRM won't work after changing the compatible name
> of ovl0 to "mediatek,mt8195-disp-ovl" in the dts.
>
> Thanks,
> Shawn

You don't have to change anything at all in the dts.

The current mt8195.dtsi declares:
compatible = "mediatek,mt8195-disp-ovl", "mediatek,mt8183-disp-ovl";

..this is enough to get the mediatek,mt8195-disp-ovl match in mtk_disp_ovl.

Regards,
Angelo