[alsa-devel] [RFC PATCH 2/3] ALSA:core: Add rate 24kHz

[Takashi Iwai]

On Thu, 05 Sep 2019 15:11:43 +0200,
Pierre-Louis Bossart wrote:
> 
> On 9/5/19 12:48 AM, Takashi Iwai wrote:
> > On Thu, 05 Sep 2019 07:33:00 +0200,
> > Pawel Harlozinski wrote:
> >>
> >> Adds SNDRV_PCM_RATE_24000 at the bottom to keep backward compability
> >> with alsa library.
> >>
> >> Signed-off-by: Pawel Harlozinski <pawel.harlozinski at linux.intel.com>
> >
> > No.  Such a fancy rate has to be handled inside the driver locally
> > instead of adding to the common rate.
> 
> It's not that crazy, this is supported in the HDaudio spec:
> 
> Sample Base Rate Divisor (DIV):
> 000 = Divide by 1 (48 kHz, 44.1 kHz)
> 001 = Divide by 2 (24 kHz, 22.05 kHz)
> 
> I am not sure why 22.05 made the cut and not 24 kHz, they are both
> derived from common clocks with the same divider... Same for 11.025
> and 12...

I'm not against supporting it.  It'd be fine if it were the changes
that are applied only to HD-audio driver side.  What I'm against is to
change the ALSA PCM core.  It's not necessarily done there at all.


thanks,

Takashi