From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Cc: alsa-devel@alsa-project.org, Liam Girdwood <lrg@slimlogic.co.uk>
Subject: Re: [PATCH] ASoC: core: Fix race in dapm_power_widgets
Date: Thu, 4 Nov 2010 09:43:54 -0400 [thread overview]
Message-ID: <20101104134354.GA1201@opensource.wolfsonmicro.com> (raw)
In-Reply-To: <1288858605-8388-1-git-send-email-peter.ujfalusi@nokia.com>
On Thu, Nov 04, 2010 at 10:16:45AM +0200, Peter Ujfalusi wrote:
> The exisiting card->mutex can not be used for this purpose,
> since it has been taken in probe time in the
> snd_soc_instantiate_card function. Through probe calls from
> this function eventually dapm_power_widgets will be called,
> which will lead to dead lock.
Hrm. You're right that the card mutex has issues here but just adding a
lock here leaves us with a race - whenever we make a change to widget
power we're doing a read/modify/write cycle and those aren't locked at
all. I'm not sure if we need a lower level lock to fix that, or a
higher level lock which would make this one redundant but we ought to
think about it and make sure we've picked the right way.
next prev parent reply other threads:[~2010-11-04 13:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-04 8:16 [PATCH] ASoC: core: Fix race in dapm_power_widgets Peter Ujfalusi
2010-11-04 9:51 ` Liam Girdwood
2010-11-04 13:43 ` Mark Brown [this message]
2010-11-04 14:18 ` Peter Ujfalusi
2010-11-04 18:08 ` Mark Brown
2010-11-05 7:53 ` Peter Ujfalusi
2010-11-05 14:38 ` Mark Brown
2010-11-06 11:00 ` Liam Girdwood
2010-11-06 15:10 ` Mark Brown
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