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References: <20220706191442.1150634-1-swboyd@chromium.org>
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From:   Doug Anderson <dianders@chromium.org>
Date:   Fri, 8 Jul 2022 08:25:44 -0700
Message-ID: <CAD=FV=UrYCwm2ByN_5EN3fq-ayMJNjmWfJ5sooRy51ZiCoMcjA@mail.gmail.com>
Subject: Re: [PATCH] drm/msm/dsi: Set panel orientation when directly connected
To:     Stephen Boyd <swboyd@chromium.org>
Cc:     Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>, patches@lists.linux.dev,
        Sean Paul <sean@poorly.run>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        freedreno <freedreno@lists.freedesktop.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>
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Precedence: bulk

Hi,

On Wed, Jul 6, 2022 at 12:14 PM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Set the panel orientation in drm when the panel is directly connected,
> i.e. we're not using an external bridge. The external bridge case is
> already handled by the panel bridge code, so we only update the path we
> take when the panel is directly connected/internal. This silences a
> warning splat coming from __drm_mode_object_add() on Wormdingler boards.
>
> Cc: Hsin-Yi Wang <hsinyi@chromium.org>
> Cc: Douglas Anderson <dianders@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>
> This relies on commit 5e41b01a7808 ("drm/panel: Add an API to allow drm
> to set orientation from panel") which is in drm-misc
>
>  drivers/gpu/drm/msm/dsi/dsi_manager.c | 2 ++
>  1 file changed, 2 insertions(+)

I don't personally have objections to this, but (to my understanding)
"the future" is that everyone should use panel_bridge. If we made the
move to panel_bridge today then we wouldn't need to do this. In
general I think panel_bridge would end up letting us delete a bunch of
code...

See commit 4e5763f03e10 ("drm/bridge: ti-sn65dsi86: Wrap panel with
panel-bridge") for when this was done by ti-sn65dsi86.

Then again, I spent a small amount of time looking into this and it's
definitely non-trivial. Still likely worthwhile, but not worth
blocking a tiny fix like this. It also should be fairly obvious that
we should delete this when we switch to panel_bridge.

Thus:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

I'll assume that we'll just snooze this commit until drm-misc-next
merges into a tree that msm-next is based on, which will probably be
the next -rc1. If desired and Acked I could land this in
drm-misc-next, but it's probably not worth it?