linux-kernel - Re: [PATCH v2] ALSA: hda: Balance runtime/system PM if direct-complete is disabled

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Message-ID: <s5him7texmh.wl-tiwai@suse.de>
Date:   Tue, 19 Jan 2021 16:48:22 +0100
From:   Takashi Iwai <tiwai@...e.de>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>
Cc:     tiwai@...e.com, "Kenneth R . Crudup" <kenny@...ix.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        Kai Vehmanen <kai.vehmanen@...ux.intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Mark Brown <broonie@...nel.org>,
        Harsha Priya <harshapriya.n@...el.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        alsa-devel@...a-project.org (moderated list:SOUND),
        linux-kernel@...r.kernel.org (open list)
Subject: Re: [PATCH v2] ALSA: hda: Balance runtime/system PM if direct-complete is disabled

On Tue, 19 Jan 2021 16:21:43 +0100,
Kai-Heng Feng wrote:
> 
> After hibernation, HDA controller can't be runtime-suspended after
> commit 215a22ed31a1 ("ALSA: hda: Refactor codjc PM to use
> direct-complete optimization"), which enables direct-complete for HDA
> codec.
> 
> The HDA codec driver didn't expect direct-complete will be disabled
> after it returns a positive value from prepare() callback. However,
> there are some places that PM core can disable direct-complete. For
> instance, system hibernation or when codec has subordinates like LEDs.
> 
> So if the codec is prepared for direct-complete but PM core still calls
> codec's suspend or freeze callback, partially revert the commit and take
> the original approach, which uses pm_runtime_force_*() helpers to
> ensure PM refcount are balanced. Meanwhile, still keep prepare() and
> complete() callbacks to enable direct-complete and request a resume for
> jack detection, respectively.
> 
> Reported-by: Kenneth R. Crudup <kenny@...ix.com>
> Fixes: 215a22ed31a1 ("ALSA: hda: Refactor codec PM to use direct-complete optimization")
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
> ---
> v2:
>  - Use pm_runtime_force_*() helpers to avoid suspend/resume ping pong.

Thanks, applied now.


Takashi