On 2023-08-22 5:07 PM, Takashi Iwai wrote:
On Tue, 22 Aug 2023 17:03:02 +0200, Jaroslav Kysela wrote:
On 11. 08. 23 18:48, Cezary Rojewski wrote:
+#define SNDRV_PCM_SUBFMTBIT_MSBITS_32 _SNDRV_PCM_SUBFMTBIT(MSBITS_32)
What was reason to add 32/32 format ? Subformat STD + msbits == 32 should already handle the maximal resolution. Until we do not have 64 bit formats, it seems like an useless extension.
My understanding is to distinguish the cases "we do fully support 32bit" and "we don't care". But, the end effect is same for both, user-space would handle 32bit in both cases, so this difference won't help much, indeed.
Bull's eye. We do want to be able to distinguish between "default" and "must be 32/32" cases. In fact we do have a test where each iteration takes a different --subformat option. On some configurations, iteration with --subformat=MSBITS_32 is expected to fail and PCM device remains closed - negative test case. If given configuration supports up to 24/32, then 32/32 shall not be allowed. Option --subformat=STD is expected to select the default max e.g.: 24/32.
Czarek