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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Thu, 14 Apr 2022 12:40:29 -0700
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Subject: Re: [PATCH v7 1/4] drm/msm/dp: Add eDP support via aux_bus
To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Doug Anderson <dianders@chromium.org>,
        Sankeerth Billakanti <quic_sbillaka@quicinc.com>
Cc:     dri-devel <dri-devel@lists.freedesktop.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        freedreno <freedreno@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>, devicetree@vger.kernel.org,
        Rob Clark <robdclark@gmail.com>,
        Sean Paul <seanpaul@chromium.org>,
        quic_kalyant <quic_kalyant@quicinc.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Kuogee Hsieh <quic_khsieh@quicinc.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        quic_vproddut <quic_vproddut@quicinc.com>,
        Aravind Venkateswaran <quic_aravindh@quicinc.com>,
        Steev Klimaszewski <steev@kali.org>
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Quoting Dmitry Baryshkov (2022-04-14 12:16:14)
>
> I think it's too verbose and a bit incorrect.
> This is a bit saner:
> /*
>   * These ops do not make sense for eDP, since they are provided
>   * by the panel-bridge corresponding to the attached eDP panel.
>   */
>
> My question was whether we really need to disable them for eDP since for
> eDP the detect and and get_modes will be overridden anyway.

And to go further, I'd expect that a bridge should expose the
functionality that it supports, regardless of what is connected down the
chain. Otherwise we won't be able to mix and match bridges because the
code is brittle, making assumptions about what is connected.