[PATCH v2 05/14] ALSA: pcm: Add DRM helper to set constraint for format

[Takashi Iwai]

On Fri, 04 Dec 2015 12:08:26 +0100,
Subhransu S. Prusty wrote:
> 
> On Thu, Dec 03, 2015 at 04:57:14PM +0100, Takashi Iwai wrote:
> > On Thu, 03 Dec 2015 22:08:53 +0100,
> > Subhransu S. Prusty wrote:
> > > 
> > > Setting the constraint format based on ELD was missing bit in
> > > the sound/core pcm drm. Added with this patch.
> > 
> > No, you can't define these here.  The format really depends on the
> > hardware, while the rate and the channels are independent.
> 
> Probably then I will move this definition to driver.
> 
> > How do you know it's little-endian?  And why it must be S24_LE for
> > 24bit, not S32_LE?
> 
> Regarding the little-endian, In the driver I think I should set the
> constraint for both LE and BE. And the platform as it only supports LE alone
> it will set the constraint accordingly and edianness will be taken care of.
> 
> Regarding the sample size, from short audio descriptor, the samples can be
> one of 16/20/24 bit. I could use the format bits for 16 and 24 bits but
> don't know which format bits macro is suitable for 20bits. So kept it as
> S32_LE for 20bits. Should I fix the format bits for 20bits to use S24?

No you seem misunderstanding the concept...


Takashi