On Fri, Oct 08, 2010 at 08:26:52AM +0200, Clemens Ladisch wrote:
Felix Homann wrote:
@Daniel: You asked for the output of lsusb. Are you thinking of modifying the UA-101 driver yourself? Or something more generic?
I guess he wanted to look for UAC2 descriptors (which this device does not have).
Actually, I wanted to check whether the device marks the inbound (capture) endpoint as isochronous with implicit data feedback usage. Which it doesn't either.
When (if) the driver has UAC2 implicit feedback support, it's easy to add a simple quirk that makes the FTU work. (In that case, the UA-101 driver can be merged back, too.)
I wonder if we can always fall back to implicit feedback in case a playback substream does not have a syncpipe and does not have its fill_max bit set.
Felix, can you add a
printk(KERN_WARNING "%s() is_playback %d fill_max %d syncpipe %d\n", __func__, is_playback, subs->fill_max, subs->syncpipe);
at the end of set_format() in pcm.c and send us the output?
I have an untested patch ready which should add support for implicit feedback, but I'm uncertain about the condition when to activate this mode.
Daniel