On Wed, 8 May 2013, Joe Rayhawk wrote:

For what it's worth, the following -stable patch

"ALSA: USB: adjust for changed 3.8 USB API" c75c5ab575af7db707689cdbb5a5c458e9a034bb

fixes the discontinuous playback on period sizes between 139 and 192, but the discontinuous playback on period sizes between 48 and 138 has been replaced by rather worse kernel blocking and kernel errors:

jrayhawk@richardiv:~$ sudo tail -F -n 0 /var/log/kern.log & [1] 4490 jrayhawk@richardiv:~$ time perl -e 'print pack "H*", "00FF" x 2048' | aplay --period-size=192 -r 48000 -f S16_LE -c2 -D hw:0,0 Playing raw data 'stdin' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo

real 0m0.053s user 0m0.008s sys 0m0.000s jrayhawk@richardiv:~$ time perl -e 'print pack "H*", "00FF" x 2048' | aplay --period-size=48 -r 48000 -f S16_LE -c2 -D hw:0,0 Playing raw data 'stdin' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo May 8 17:01:56 richardiv kernel: [ 1680.923474] cannot submit urb (err = -18) May 8 17:01:56 richardiv kernel: [ 1680.924472] cannot submit urb (err = -18)

real 0m10.023s user 0m0.008s sys 0m0.004s

I don't know if you want to investigate this in any detail. If you do, please post a usbmon trace of a failed playback.

Alan Stern

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