linux-kernel - Re: Re: Re: [PATCH 07/17] ASoC: twl6040: Lower the initial gains

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Message-ID: <20110921123931.GD4374@opensource.wolfsonmicro.com>
Date:	Wed, 21 Sep 2011 13:39:31 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Péter Ujfalusi <peter.ujfalusi@...com>
Cc:	Samuel Ortiz <samuel.ortiz@...el.com>,
	Dmitry Torokhov <dtor@...l.ru>, Liam Girdwood <lrg@...com>,
	alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
	Misael Lopez Cruz <misael.lopez@...com>
Subject: Re: Re: Re: [PATCH 07/17] ASoC: twl6040: Lower the initial gains

On Wed, Sep 21, 2011 at 12:22:26PM +0300, Péter Ujfalusi wrote:

> The implementation in twl6040 looks similar to the one in the wm8350 in 
> regards to the ramp code, and caching of the user configured gains.

Yes, it was copied from there.

> If you take a look at the wm8350 driver it is also changing the L/R OUT 1/2 
> registers at probe time.
> I don't see any difference in the two.

The key problem here is that you sent a change saying "change the
default volume" with no other context in either the changelog or the
code.  If you've got code that's actively managing the volume register
while presenting a nice view to the application layer so that the
register value isn't directly seen in the way it is for standard ASoC
controls that's a very different thing to standard code.  I'm not going
to remember the details of everything in every CODEC driver.

> We do have other scenarios covered, but this initialization was missing. This 
> resulted that the _first_ playback has pop noise, but all subsequent playbacks 
> were fine, since we had the runtime fix for this.

So what you're doing here is really a bug fix for the ramping code.
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