Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device

From: Vinod Koul
Date: Sun Dec 06 2020 - 23:44:20 EST


On 05-12-20, 08:59, Pierre-Louis Bossart wrote:
> Thanks for the review Vinod.
>
> On 12/5/20 1:45 AM, Vinod Koul wrote:
> > On 03-12-20, 04:46, Bard Liao wrote:
> > > From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> > >
> > > When a Slave device is resumed, it may resume the bus and restart the
> > > enumeration. During that process, we absolutely don't want to call
> > > regular read/write routines which will wait for the resume to
> > > complete, otherwise a deadlock occurs.
> > >
> > > Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')
> >
> > Change looks okay, but not sure why this is a fix for adding no pm
> > version?
>
> when we added the no_pm version, we missed the two cases below where
> sdw_update() was used and that creates a deadlock. To me that's a conceptual
> bug, we didn't fully use the no_pm versions, hence the Fixes tag.

Documentation says:
"A Fixes: tag indicates that the patch fixes an issue in a previous commit. It
is used to make it easy to determine where a bug originated, which can help
review a bug fix. This tag also assists the stable kernel team in determining
which stable kernel versions should receive your fix. This is the preferred
method for indicating a bug fixed by the patch. See :ref:`describe_changes`
for more details."

I do not this this helps here as this does not help distros etc
I would say this is incremental development which improved a case not
done properly earlier, unless you would like this to be backported.. In
that case it helps folks...

> It's ok to remove the tag if you don't think it's useful/relevant, what
> matters is that we agree on the content.

--
~Vinod