linux-kernel - Re: [PATCH -next] drm/bridge: Add missing clk_disable_unprepare() in analogix_dp

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Message-ID: <YwQqMCNBiafBjDSw@google.com>
Date:   Mon, 22 Aug 2022 18:15:28 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Zhang Zekun <zhangzekun11@...wei.com>
Cc:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Robert Foss <robert.foss@...aro.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Doug Anderson <dianders@...omium.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        xuqiang36@...wei.com
Subject: Re: [PATCH -next] drm/bridge: Add missing clk_disable_unprepare() in
 analogix_dp_resume()

Hi,

On Wed, Aug 17, 2022 at 05:05:25PM -0700, Brian Norris wrote:
> Hmm, actually I'm going to have to retract that now that I've given it
> some more testing locally. I happen to have a system where I commonly
> hit this error case, and I'm thinking commit 211f276ed3d9 is actually
> wrong, and so we shouldn't be "fixing" its error handling -- we should
> be reverting it.

I've submitted that for review here:
https://lore.kernel.org/all/20220822180729.1.I8ac5abe3a4c1c6fd5c061686c6e883c22f69022c@changeid/
[PATCH] Revert "drm: bridge: analogix/dp: add panel prepare/unprepare in suspend/resume time"

I'd appreciate your review/testing.

(NB: I failed to honor the .mailmap for Andrzej Hajda.)

> Now separately, I have to figure out why I'm hitting this error case in
> the first place...

FWIW, I captured the reason in point 3 on the above Revert. The
pm_runtime_*() handling in the panel driver fails (-EACCES) because the
bridge driver is resuming before the panel. (The DRM suspend/resume
helpers handle things in the correct order.)

This problem is also resolved by simply reverting.

Brian