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Subject: Re: [PATCH v2 0/5] 180 degrees rotation support for NVIDIA Tegra DRM
To:     Daniel Stone <daniel@fooishbar.org>
Cc:     Emil Velikov <emil.l.velikov@gmail.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
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        Sam Ravnborg <sam@ravnborg.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
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        ML dri-devel <dri-devel@lists.freedesktop.org>
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From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <36496bd6-b18a-de97-1afb-f2f8aeb3feaf@gmail.com>
Date:   Wed, 17 Jun 2020 19:27:18 +0300
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17.06.2020 12:34, Daniel Stone пишет:
> Hi,
> 
> On Tue, 16 Jun 2020 at 22:16, Dmitry Osipenko <digetx@gmail.com> wrote:
>> The panel's orientation could be parsed by any panel driver and then
>> assigned as the connector's property in order to allow userspace/FB-core
>> to decide what to do with the rotated display. Apparently upstream
>> kernel supports only that one Samsung device which has display panel
>> mounted upside-down and it already uses the custom DT properties for
>> achieving the 180 rotation. So I don't quite see any panel drivers that
>> instantly could benefit from using the rotation property. Perhaps I can
>> add the orientation support to the panel-simple driver, but will it be
>> useful to anyone?
> 
> Yes, exposing it to userspace is helpful, since Weston at least will
> parse the property and then apply the correct transform:
> https://gitlab.freedesktop.org/wayland/weston/-/merge_requests/315

Hello Daniel,

Thank you very much for the pointer! I missed that Weston now uses the
panel's orientation. I gave a quick test to the recent Weston and indeed
it applies the transform in accordance to the connector's orientation
property.