[alsa-devel] [PATCH] Add ASoC WM9713 codec driver.
cladisch at fastmail.net
Tue Nov 20 13:02:00 CET 2007
Takashi Iwai wrote:
> Mark Brown wrote:
> > +#define WM9713_PCM_FORMATS \
> > + (SNDRV_PCM_FORMAT_S16_LE | SNDRV_PCM_FORMAT_S20_3LE | \
> > + SNDRV_PCM_FORMAT_S24_LE)
> Is it S24_LE or S24_3LE? I see S24_LE in other codec drivers, but am
> not pretty sure whether I checked it...
Apparently, these are the formats that an AC'97 controller connected
with this codec can support.
Samples on the AC'97 bus are always MSB-aligned with at most 20 bits.
I don't think it makes much sense to let the codec driver decide what
sample formats the controller should support, because the controller
will have to convert the samples anyway (from/to 16, 24 or 32 bits).
Furthermore, I'm sure there are AC'97 controllers that can handle big-
endian samples on the memory bus.
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