Re: [PATCH] drm: docs: Remove item from TODO list

From: Doug Anderson <dianders@chromium.org>
To: Yuran Pereira <yuran.pereira@hotmail.com>
Cc: neil.armstrong@linaro.org, tzimmermann@suse.de, corbet@lwn.net,
	sam@ravnborg.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, mripard@kernel.org,
	christian.koenig@amd.com, linaro-mm-sig@lists.linaro.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	dri-devel@lists.freedesktop.org, sumit.semwal@linaro.org,
	linux-media@vger.kernel.org
Subject: Re: [PATCH] drm: docs: Remove item from TODO list
Date: Mon, 23 Oct 2023 10:25:50 -0700	[thread overview]
Message-ID: <CAD=FV=W0G6C-=99viHMQaW2REGRQr2xgaejnJmadOdZkoE7AjA@mail.gmail.com> (raw)
In-Reply-To: <DB3PR10MB683528B8252ED2A802A0E154E8D8A@DB3PR10MB6835.EURPRD10.PROD.OUTLOOK.COM>

Hi,

On Mon, Oct 23, 2023 at 9:31 AM Yuran Pereira <yuran.pereira@hotmail.com> wrote:
>
> Since "Clean up checks for already prepared/enabled in panels" has
> already been done and merged [1], I think there is no longer a need
> for this item to be in the gpu TODO.
>
> [1] https://patchwork.freedesktop.org/patch/551421/
>
> Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com>
> ---
>  Documentation/gpu/todo.rst | 25 -------------------------
>  1 file changed, 25 deletions(-)

It's not actually all done. It's in a bit of a limbo state right now,
unfortunately. I landed all of the "simple" cases where panels were
needlessly tracking prepare/enable, but the less simple cases are
still outstanding.

Specifically the issue is that many panels have code to properly power
cycle themselves off at shutdown time and in order to do that they
need to keep track of the prepare/enable state. After a big, long
discussion [1] it was decided that we could get rid of all the panel
code handling shutdown if only all relevant DRM KMS drivers would
properly call drm_atomic_helper_shutdown().

I made an attempt to get DRM KMS drivers to call
drm_atomic_helper_shutdown() [2] [3] [4]. I was able to land the
patches that went through drm-misc, but currently many of the
non-drm-misc ones are blocked waiting for attention.

...so things that could be done to help out:

a) Could review patches that haven't landed in [4]. Maybe adding a
Reviewed-by tag would help wake up maintainers?

b) Could see if you can identify panels that are exclusively used w/
DRM drivers that have already been converted and then we could post
patches for just those panels. I have no idea how easy this task would
be. Is it enough to look at upstream dts files by "compatible" string?

I've gotten side-tracked at the moment so I haven't been driving
progress on this very quickly. I still plan to poke some of the
drm_atomic_helper_shutdown() patches eventually...

[1] https://lore.kernel.org/r/20230804140605.RFC.4.I930069a32baab6faf46d6b234f89613b5cec0f14@changeid
[2] https://lore.kernel.org/r/20230901234015.566018-1-dianders@chromium.org
[3] https://lore.kernel.org/r/20230901234202.566951-1-dianders@chromium.org
[4] https://lore.kernel.org/r/20230921192749.1542462-1-dianders@chromium.org