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References: <20220601094637.1200634-1-hsinyi@chromium.org>
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From:   Doug Anderson <dianders@chromium.org>
Date:   Thu, 2 Jun 2022 14:48:20 -0700
Message-ID: <CAD=FV=W+5GAUBh_ZMPeKhqxQXxau2OKCbt3p2QmsDhROf207dA@mail.gmail.com>
Subject: Re: [PATCH v2 0/8] Add a panel API to return panel orientation
To:     Hsin-Yi Wang <hsinyi@chromium.org>
Cc:     Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Rob Clark <robdclark@chromium.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Rob Herring <robh+dt@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>
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Hi,

On Wed, Jun 1, 2022 at 2:46 AM Hsin-Yi Wang <hsinyi@chromium.org> wrote:
>
> Panels usually call drm_connector_set_panel_orientation(), which is
> later than drm/kms driver calling drm_dev_register(). This leads to a
> WARN()[1].
>
> The orientation property is known earlier. For example, some panels
> parse the property through device tree during probe.
>
> The series add a panel API drm_panel_get_orientation() for drm/kms
> drivers. The drivers can use the API to get panel's orientation, so they
> can call drm_connector_set_panel_orientation() before drm_dev_register().
>
> Panel needs to implement .get_orientation callback to return the property.
>
> [1] https://patchwork.kernel.org/project/linux-mediatek/patch/20220530081910.3947168-2-hsinyi@chromium.org/
>
> Hsin-Yi Wang (8):
>   drm/panel: Add an API drm_panel_get_orientation() to return panel
>     orientation
>   drm/panel: boe-tv101wum-nl6: Implement .get_orientation callback
>   drm/panel: panel-edp: Implement .get_orientation callback
>   drm/panel: lvds: Implement .get_orientation callback
>   drm/panel: panel-simple: Implement .get_orientation callback
>   drm/panel: ili9881c: Implement .get_orientation callback
>   drm/panel: elida-kd35t133: Implement .get_orientation callback
>   drm/mediatek: Config orientation property if panel provides it
>
>  drivers/gpu/drm/drm_panel.c                    |  8 ++++++++
>  drivers/gpu/drm/mediatek/mtk_dsi.c             | 10 ++++++++++
>  drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c |  8 ++++++++
>  drivers/gpu/drm/panel/panel-edp.c              |  8 ++++++++
>  drivers/gpu/drm/panel/panel-elida-kd35t133.c   |  8 ++++++++
>  drivers/gpu/drm/panel/panel-ilitek-ili9881c.c  |  8 ++++++++
>  drivers/gpu/drm/panel/panel-lvds.c             |  8 ++++++++
>  drivers/gpu/drm/panel/panel-simple.c           |  9 +++++++++
>  include/drm/drm_panel.h                        | 10 ++++++++++
>  9 files changed, 77 insertions(+)

Seems reasonable to me. I added a request to the panel-edp patch that
probably applies to all of the panel patches requesting a comment next
to the old calls in get_modes().

I assume that all but patch #8 ought to land through drm-misc. I'm
happy to help commit them once everyone is happy. If the Mediatek
maintainer(s) want to Ack patch #8 I can land that in drm-misc too. If
we want something fancier like an immutable branch you'll probably
have to get someone involved that's got a higher drm pay grade than
me. ;-)

-Doug