linux-kernel - Re: [PATCH v2] drm/bridge: parade-ps8640: Ensure bridge is suspended in .post

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Date: Tue, 9 Jan 2024 08:52:12 -0800
From: Doug Anderson <dianders@...omium.org>
To: Pin-yen Lin <treapking@...omium.org>
Cc: Andrzej Hajda <andrzej.hajda@...el.com>, Neil Armstrong <neil.armstrong@...aro.org>, 
	Robert Foss <rfoss@...nel.org>, Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
	Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
	dri-devel@...ts.freedesktop.org, Sean Paul <seanpaul@...omium.org>, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/bridge: parade-ps8640: Ensure bridge is suspended
 in .post_disable()

Hi,

On Tue, Jan 9, 2024 at 4:05 AM Pin-yen Lin <treapking@...omium.org> wrote:
>
> The ps8640 bridge seems to expect everything to be power cycled at the
> disable process, but sometimes ps8640_aux_transfer() holds the runtime
> PM reference and prevents the bridge from suspend.
>
> Prevent that by introducing a mutex lock between ps8640_aux_transfer()
> and .post_disable() to make sure the bridge is really powered off.
>
> Fixes: 826cff3f7ebb ("drm/bridge: parade-ps8640: Enable runtime power management")
> Signed-off-by: Pin-yen Lin <treapking@...omium.org>
> ---
>
> Changes in v2:
> - Use mutex instead of the completion and autosuspend hack
>
>  drivers/gpu/drm/bridge/parade-ps8640.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)

This looks OK to me now.

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

I'll let it stew on the mailing list for ~1 week and then land it in
drm-misc-fixes unless there are additional comments.

-Doug