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From:   Doug Anderson <dianders@chromium.org>
Date:   Mon, 1 Nov 2021 11:02:09 -0700
Message-ID: <CAD=FV=Xoaypn6wy5mHfTneDrQYexGcdcaMqkSnPJf0YS=jHpPA@mail.gmail.com>
Subject: Re: [PATCH] drm/msm/dsi: set default num_data_lanes
To:     Philip Chen <philipchen@chromium.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Rob Clark <robdclark@chromium.org>,
        Abhinav Kumar <abhinavk@codeaurora.org>,
        Bernard Zhao <bernard@vivo.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Jonathan Marek <jonathan@marek.ca>,
        Nicolas Boichat <drinkcat@chromium.org>,
        Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Yangtao Li <tiny.windzz@gmail.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        freedreno <freedreno@lists.freedesktop.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>
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Hi,

On Sat, Oct 30, 2021 at 10:08 AM Philip Chen <philipchen@chromium.org> wrote:
>
> If "data_lanes" property of the dsi output endpoint is missing in
> the DT, num_data_lanes would be 0 by default, which could cause
> dsi_host_attach() to fail if dsi->lanes is set to a non-zero value
> by the bridge driver.
>
> According to the binding document of msm dsi controller, the
> input/output endpoint of the controller is expected to have 4 lanes.
> So let's set num_data_lanes to 4 by default.
>
> Signed-off-by: Philip Chen <philipchen@chromium.org>
> ---
>
>  drivers/gpu/drm/msm/dsi/dsi_host.c | 2 ++
>  1 file changed, 2 insertions(+)

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