Re: [PATCH] Revert "arm64: dts: mediatek: mt8173-elm: Move display to ps8640 auxiliary bus"

[Pin-yen Lin]

Hi all,

I would like to drop this patch because 102e80d1fa2c ("drm/bridge:
ps8640: Use atomic variants of drm_bridge_funcs") breaks the
ps8640_bridge_get_edid function. The atomic helper requires an atomic
state to do the chain enablement, but we don't have that in the
.get_edid callback.

The latest ChromeOS tree uses the "aux-bus" with "edp-panel"
compatible string, and it seems to be working well. I'll upload
another patch to update this.

Best regards,
Pin-yen

On Wed, Mar 15, 2023 at 6:34 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
>
> Il 15/03/23 05:11, Pin-yen Lin ha scritto:
> > This reverts commit c2d94f72140a28d0f516b7c5e8274a9c185a04ff.
> >
> > The `lg_lp120up1_mode` defined in panel-edp.c is not working for some
> > panels used on elm/hana devices. Move the panel node out of the aux-bus
> > subnode so the driver only uses the modes retrieved from the EDID.
> >
> > Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx>
> >
>
> This commit was sent to fix display functionality on MT8173-Elm (Acer Chromebook
> R13).... apparently this should get fixed with [1].
>
> Investigating if this is the case.
>
> Regards,
> Angelo
>
> [1]:
> https://patchwork.kernel.org/project/dri-devel/patch/20230315035508.2874915-1-treapking@xxxxxxxxxxxx/
>
> > ---
> >
> >   arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi | 26 +++++++++-----------
> >   1 file changed, 12 insertions(+), 14 deletions(-)
> >
> > diff --git a/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi b/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi
> > index d452cab28c67..d45a2aeb0eb1 100644
> > --- a/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi
> > +++ b/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi
> > @@ -90,6 +90,18 @@ switch-volume-up {
> >               };
> >       };
> >
> > +     panel: panel {
> > +             compatible = "lg,lp120up1";
> > +             power-supply = <&panel_fixed_3v3>;
> > +             backlight = <&backlight>;
> > +
> > +             port {
> > +                     panel_in: endpoint {
> > +                             remote-endpoint = <&ps8640_out>;
> > +                     };
> > +             };
> > +     };
> > +
> >       panel_fixed_3v3: regulator1 {
> >               compatible = "regulator-fixed";
> >               regulator-name = "PANEL_3V3";
> > @@ -282,20 +294,6 @@ ps8640_out: endpoint {
> >                               };
> >                       };
> >               };
> > -
> > -             aux-bus {
> > -                     panel: panel {
> > -                             compatible = "lg,lp120up1";
> > -                             power-supply = <&panel_fixed_3v3>;
> > -                             backlight = <&backlight>;
> > -
> > -                             port {
> > -                                     panel_in: endpoint {
> > -                                             remote-endpoint = <&ps8640_out>;
> > -                                     };
> > -                             };
> > -                     };
> > -             };
> >       };
> >   };
> >
>