linux-kernel - RE: [alsa-devel] [PATCH] ASoC: wm8962: Correct the bit offset to enable mono speaker output

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Date:	Wed, 13 Aug 2014 10:10:02 +0000
From:	Peter Chan <peter.chan@...escale.com>
To:	Mark Brown <broonie@...nel.org>,
	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
CC:	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	"tiwai@...e.de" <tiwai@...e.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"patches@...nsource.wolfsonmicro.com" 
	<patches@...nsource.wolfsonmicro.com>,
	"shengjiu.wang@...escale.com" <shengjiu.wang@...escale.com>,
	"lgirdwood@...il.com" <lgirdwood@...il.com>,
	Nicolin Chen <nicoleotsuka@...il.com>,
	"guangyu.chen@...escale.com" <guangyu.chen@...escale.com>,
	"rf@...nsource.wolfsonmicro.com" <rf@...nsource.wolfsonmicro.com>
Subject: RE: [alsa-devel] [PATCH] ASoC: wm8962: Correct the bit offset to
 enable mono speaker output

I found that in mono speaker mode, only the left channel is enable. The SPKOUTR_PGA_ENA bit remains 0 in this case. Thus when SPKOUTR_ENA is set, poor sound quality results.

-----Original Message-----
From: Mark Brown [mailto:broonie@...nel.org] 
Sent: Wednesday, August 13, 2014 5:58 AM
To: Charles Keepax
Cc: CHAN Peter-B18700; alsa-devel@...a-project.org; tiwai@...e.de; linux-kernel@...r.kernel.org; patches@...nsource.wolfsonmicro.com; Wang Shengjiu-B02247; lgirdwood@...il.com; Nicolin Chen; Chen Guangyu-B42378; rf@...nsource.wolfsonmicro.com
Subject: Re: [alsa-devel] [PATCH] ASoC: wm8962: Correct the bit offset to enable mono speaker output

On Tue, Aug 12, 2014 at 09:24:16AM +0100, Charles Keepax wrote:
> On Mon, Aug 11, 2014 at 02:19:49PM +0100, Charles Keepax wrote:

> > From the wording of "tie both outputs together" in the datasheet I 
> > would assume that means both should be fed the same audio? Was this 
> > done? I will try to give the hardware guys here a shout and see if I 
> > can get some clarification on mono mode on this device.

> I have had a word with the hardware team here and both channels do 
> need to be enabled but audio should only be fed to the left channel. 
> So the driver definitely needs updated for the mono case, but I am 
> unclear as to what is causing your poor audio quality issue.

Overdriving the speaker perhaps?
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