On Sat, Dec 05, 2015 at 09:12:34AM +0100, Takashi Iwai wrote: > On Sat, 05 Dec 2015 12:27:03 +0100, > Subhransu S. Prusty wrote: > > > > On Fri, Dec 04, 2015 at 06:59:19AM +0100, Takashi Iwai wrote: > > > 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... > > > > Sorry about that. > > > > I re-read the spec, it doesn't mention the container size for the samples. > > Assuming the container will be 32 bits, then I think we should use S24_LE > > for both 20 and 24 bits. > > You can't limit easily from the supported bits. In theory, all > formats that may fit with the given bit should be set. For example, > for a 20bit sample, S24, U24, S32, U32, S24_3, U24_3, S20_3, etc would > match, and even for both endianess. > > The format type doesn't specify only the *max* bit it can pack, but > also only the position of bits to be packed. For example, S24 packs > max 24 bits in the lower 24 bits in a 32bit container. And, S24_3 > packs max 24 bits in a 24bit container. Most of Intel chips takes the > upper bits in a container, so usually they need S32 or S16 no matter > how many bits are used.
Thanks for the quick reply. I am thinking to set the format as S16 for 16bits and S32 for 20/24bits. But then we can set S32 for everything as well including 16bits. What do you recommend? > > > Takashi --
