Received-SPF: pass (google.com: domain of linux-kernel+bounces-4084-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Precedence: bulk
MIME-Version: 1.0
References: <20231214152817.2766280-1-treapking@chromium.org> <20231214152817.2766280-4-treapking@chromium.org>
In-Reply-To: <20231214152817.2766280-4-treapking@chromium.org>
From: Doug Anderson <dianders@chromium.org>
Date: Mon, 18 Dec 2023 08:42:20 -0800
Message-ID: <CAD=FV=Xd3TJNBSzUQ=4td9t6Nqnbd3QAt7fmnn_aT0QXSkRn0Q@mail.gmail.com>
Subject: Re: [PATCH v3 3/3] drm/panel-edp: Add some panels with conservative timings
To: Pin-yen Lin <treapking@chromium.org>
Cc: Neil Armstrong <neil.armstrong@linaro.org>, Jessica Zhang <quic_jesszhan@quicinc.com>, 
	Sam Ravnborg <sam@ravnborg.org>, Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, 
	Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, 
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, Guenter Roeck <groeck@chromium.org>, 
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Hi,

On Thu, Dec 14, 2023 at 7:28=E2=80=AFAM Pin-yen Lin <treapking@chromium.org=
> wrote:
>
> These panels are used by Mediatek MT8173 Chromebooks, and they used to
> work with the downstream v4.19 kernel without any specified delay.
> Back in the v4.19 kernel, they used the "little white lie" approach,
> which is making the devicetree claim a specific panel's compatible
> string for many different panels. That was a common solution before the
> generic edp-panel driver.
>
> After we uprevved the device to a newer kernel and used the edp-panel
> driver, we saw multiple devices reporting warnings of using an unknown
> panel and falling back to the conservative timings, which means that
> they turn on/off much more slowly than they should. We tried to fill in
> the timings for those panels, but we failed to find all the data sheets
> for them.
>
> Therefore, instead of having them use the default conservative timings,
> update them with less-conservative timings from other panels of the same
> vendor. The panels should still work under those timings, and we can
> save some delays and suppress the warnings.
>
> Signed-off-by: Pin-yen Lin <treapking@chromium.org>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>
> ---
>
> Changes in v3:
> - Update the commit message.
> - Collect review tag.
>
>  drivers/gpu/drm/panel/panel-edp.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)

Pushed to drm-misc-next:

7c8690d8fc80 drm/panel-edp: Add some panels with conservative timings