From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Mack <zonque@gmail.com>
Subject: Re: [PATCH] ALSA: ASoC: cs4720: use
	snd_soc_cache_sync()
Date: Tue, 22 Nov 2011 16:23:05 +0100
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To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: alsa-devel@alsa-project.org, Sven Neumann <s.neumann@raumfeld.com>, timur@freescale.com, lrg@ti.com
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On 11/22/2011 03:02 PM, Mark Brown wrote:
> On Tue, Nov 22, 2011 at 02:45:16PM +0100, Daniel Mack wrote:
>> Replace the manual register restore mechanism in cs4270.c and call
>> snd_soc_cache_sync() instead. The current is also wrong, as it doesn't
>> update the internal cache, leading to cache inconsitency after suspend.
> 
> I don't understand why this is a bug fix - the code is writing the
> values from the internal cache to the hardware and what's there doesn't
> look obviously wrong...

Hmm, you're right, that isn't obvious. I was too fast in blaming the
code wrong as it stands. But as a matter of fact, the patch *does* fix
the problem, Sven successfully tested it on various devices.

The bug is reproducible by setting the output volume to 50% before
sending the device to suspend. After wakeup, amixer still reports the
old volume level, but the codec is in fact set to 100%. Changing it to
50% doesn't do anything, but to any other level has an effect. This is
clearly a cache sync bug, but the piece that's missing is the reason why
my patch does the right thing.

I'll look into this again - thanks for the heads-up.