(Moving this discussion from sdr-widget to alsa-devel. Can't Cc: the original mailing list as it forbids cross-posting) On Thu, Jun 10, 2010 at 09:36:48PM -0700, Alex Lee wrote: > I studied the driver source again and it becomes apparent that the > driver only looks at the MIN value of the triplet (MIN, MAX, RES). It > does not take into consideration of the MAX and the RES in each > triplet. For samplerates it does that, yes. > The driver calculates its own MIN and MAX values by going through all > the triplets in the clock source. In the present firmware, we only > have ONE triplet in each clock source, with: > > # of triplets = 1 (2 byte value) > MIN 48000 > MAX 96000 > RES 48000 Ah, that's a corner case I didn't see. I'll fix this. > in accordance with the UAC2 specs. The present driver code expects: > > # of triplets = 2 (2 byte value) > triplet 1: > > MIN 48000 MAX 48000 RES 00000 > > triplet 2: > > MIN 96000 MAX 96000 RES 00000 Yes, that's right. All firmware code I've seen so far also has a triplet for each discrete sample rate. > Thus the present driver cannot decode the 1st case above correctly, > and only get the 48khz value. > > I will update the firmware to cater to the 2nd case above and we > should have the 96khz back :-) Ok, fair fix. I'll make sure future versions of the driver also support the other approach. Thanks, Daniel _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
