linux-kernel - Re: [PATCH v2] media: hi846: fix usage of pm_runtime_get_if_in

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Message-ID: <ZHUNrHGJv63mKGH0@valkosipuli.retiisi.eu>
Date:   Mon, 29 May 2023 23:40:12 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Martin Kepplinger <martin.kepplinger@...i.sm>
Cc:     laurent.pinchart@...asonboard.com, kernel@...i.sm,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        mchehab@...nel.org
Subject: Re: [PATCH v2] media: hi846: fix usage of pm_runtime_get_if_in_use()

On Tue, May 23, 2023 at 12:07:54PM +0200, Martin Kepplinger wrote:
> Am Dienstag, dem 16.05.2023 um 16:22 +0300 schrieb Sakari Ailus:
> > Hi Martin,
> > 
> > On Tue, Apr 25, 2023 at 11:47:47AM +0200, Martin Kepplinger wrote:
> > > pm_runtime_get_if_in_use() does not only return nonzero values when
> > > the device is in use, it can return a negative errno too.
> > > 
> > > And especially during resuming from system suspend, when runtime pm
> > > is not yet up again, -EAGAIN is being returned, so the subsequent
> > > pm_runtime_put() call results in a refcount underflow.
> > > 
> > > Fix system-resume by handling -EAGAIN of
> > > pm_runtime_get_if_in_use().
> > > 
> > > Signed-off-by: Martin Kepplinger <martin.kepplinger@...i.sm>
> > > ---
> > > 
> > > revision history
> > > ----------------
> > > v2 (thank you Sakari and Laurent):
> > > * drop the other patch (the streaming-state in suspend/resume needs
> > > to
> > >   be solved differently).
> > > * Sakari pointed out that many drivers are affected by this and
> > > that
> > >   runtime-pm might need changes instead. I think this patch doesn't
> > > hurt
> > >   and could serve as a reminder to do so.
> > 
> > I guess it's appropriate to add:
> > 
> > Fixes: e8c0882685f9 ("media: i2c: add driver for the SK Hynix Hi-846
> > 8M pixel camera")
> > 
> 
> I agree. Feel free to do so when applying.

Done!

-- 
Sakari Ailus