Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20201231060319.137133-1-kai.heng.feng@canonical.com> <s5h7dnxxz1k.wl-tiwai@suse.de>
In-Reply-To: <s5h7dnxxz1k.wl-tiwai@suse.de>
From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
Date:   Thu, 28 Jan 2021 16:15:10 +0800
Message-ID: <CAAd53p5cg=ye5DnXAhb89HoUyJG6ecx3-OQp4ntgFumQWSnxQA@mail.gmail.com>
Subject: Re: [PATCH] PM: sleep: core: Resume suspended device if
 direct-complete is disabled
To:     Takashi Iwai <tiwai@suse.de>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        "Kenneth R . Crudup" <kenny@panix.com>,
        Pavel Machek <pavel@ucw.cz>, Len Brown <len.brown@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "open list:HIBERNATION (aka Software Suspend, aka swsusp)" 
        <linux-pm@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, Jan 28, 2021 at 4:09 PM Takashi Iwai <tiwai@suse.de> wrote:
>
> On Thu, 31 Dec 2020 07:03:19 +0100,
> Kai-Heng Feng wrote:
> >
> > 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 doesn't expect direct-complete will be disabled
> > after it returns a positive value from prepare() callback. So freeze()
> > is called directly when it's runtime-suspended, breaks the balance of
> > its internal codec_powered counting.
> >
> > So if a device is prepared for direct-complete but PM core breaks the
> > assumption, resume the device to keep PM operations balanced.
> >
> > Fixes: 215a22ed31a1 ("ALSA: hda: Refactor codec PM to use direct-complete optimization")
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>
> Kai-Heng, is this fix still needed for 5.11?

No it's not needed anymore because "ALSA: hda: Balance runtime/system
PM if direct-complete is disabled" is in place.

>
> The description mentions about HD-audio controller, while the recent
> revert was the HD-audio codec, so I suppose it's still affected?

Not affected anymore if above mentioned patch is applied.

Kai-Heng

>
>
> thanks,
>
> Takashi
>
> > ---
> >  drivers/base/power/main.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> > index 46793276598d..9c0e25a92ad0 100644
> > --- a/drivers/base/power/main.c
> > +++ b/drivers/base/power/main.c
> > @@ -1849,6 +1849,10 @@ static int device_prepare(struct device *dev, pm_message_t state)
> >               (ret > 0 || dev->power.no_pm_callbacks) &&
> >               !dev_pm_test_driver_flags(dev, DPM_FLAG_NO_DIRECT_COMPLETE);
> >       spin_unlock_irq(&dev->power.lock);
> > +
> > +     if (ret > 0 && !dev->power.direct_complete)
> > +             pm_runtime_resume(dev);
> > +
> >       return 0;
> >  }
> >
> > --
> > 2.29.2
> >