[alsa-devel] [PATCH 2/3] ASoC: Blackfin: add multi-channel supporting in Blackfin ASoC driver and AD1980 codec driver

[Cai, Cliff]

>-----Original Message-----
>From: Mark Brown [mailto:broonie at sirena.org.uk] 
>Sent: Tuesday, October 21, 2008 4:37 PM
>To: Bryan Wu
>Cc: alsa-devel at alsa-project.org; Cliff Cai
>Subject: Re: [PATCH 2/3] ASoC: Blackfin: add multi-channel 
>supporting in Blackfin ASoC driver and AD1980 codec driver
>
>On Tue, Oct 21, 2008 at 11:36:12AM +0800, Bryan Wu wrote:
>
>> +config SND_MULTICHAN_SUPPORT
>> +	bool "Enable Multichannel Support"
>> +	depends on SND_BF5XX_AC97
>> +	default n
>> +	help
>> +	  Say y if you want AC97 driver to support up to 5.1 
>channel audio.
>> +	  this mode will consume much more memory for DMA. 
>> +
>
>Should this be a user visible option or selected by the 
>machine drivers?

I think people want to enable this feature
Only If they really want it,since it will consume much more memory
To hold multi-channel data.
 
>To be honest, I'm surprised that the multi-channel support 
>can't only incur the extra memory consumpton when playing back 
>a multi-channel stream - I'd have expected the hardware to 
>work in the same way for a normal stereo stream even if 
>multi-channel support is built in.

Yes,hardware almost works in the same way as playing a stereo
stream,except
That it need to fill more data to DMA memory manually,since we just
simulate AC97
Controller using serial port.

>> -void bf5xx_ac97_to_pcm(const struct ac97_frame *src, __u32 *dst, \
>> +void bf5xx_ac97_to_pcm(const struct ac97_frame *src, __u16 *dst, \
>>  		size_t count)
>>  {
>
>Separately please submit a patch removing the needless 
>continuation character here.
>
>> diff --git a/sound/soc/codecs/ad1980.c b/sound/soc/codecs/ad1980.c 
>> index 1397b8e..e22fbdf 100644
>> --- a/sound/soc/codecs/ad1980.c
>> +++ b/sound/soc/codecs/ad1980.c
>
>The codec driver changes should be submitted as a separate patch.
>They're good to go as-is.
>