Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 12/01/22 08:09, Jagan Teki ha scritto:
> On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
> > DRM bridge drivers are now attaching their DSI device at probe time,
> > which requires us to register our DSI host in order to let the bridge
> > to probe: this recently started producing an endless -EPROBE_DEFER
> > loop on some machines that are using external bridges, like the
> > parade-ps8640, found on the ACER Chromebook R13.
> >
> > Now that the DSI hosts/devices probe sequence is documented, we can
> > do adjustments to the mtk_dsi driver as to both fix now and make sure
> > to avoid this situation in the future: for this, following what is
> > documented in drm_bridge.c, move the mtk_dsi component_add() to the
> > mtk_dsi_ops.attach callback and delete it in the detach callback;
> > keeping in mind that we are registering a drm_bridge for our DSI,
> > which is only used/attached if the DSI Host is bound, it wouldn't
> > make sense to keep adding our bridge at probe time (as it would
> > be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> > that one to the dsi host attach function (and remove it in detach).
> >
> > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> > Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
> > ---
>
> Eventually I've observed similar issue on other Component based DSI
> controllers, hence
>
> Reviewed-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>

Hello dri-devel,
can you please pick this patch?

All MediaTek platforms are broken in v5.17 without this one.

Thanks,
Angelo