[alsa-devel] BUG: USB audio discontinuities with 'UHCI: implement new semantics for URB_ISO_ASAP'

[Joe Rayhawk]

On Fri, Apr 19, 2013 at 02:18:24PM -0400, Alan Stern wrote:
> On Fri, 19 Apr 2013, Clemens Ladisch wrote:
> > Alan Stern wrote:
> > > +		next = uhci->frame_number + 2;
> > >
> > > That 2 is the minimum latency, in frames (one frame per ms).
> > 
> > One frame worked fine with the old driver.  What is the reason for
> > this regression?
> 
> Perhaps that was a mistake.  Joe, you can try changing the 2 above to a 
> 1 to see if it fixes the problem.

Hey, that worked great! Audio's coming through continuously, now.

root at richardiv:~# uname -a; cat /sys/kernel/debug/usb/usbmon/4u & perl -e 'print pack "H*", "00FF" x 2048' | aplay --period-size=48 -r 44100 -f S16_LE -c2 -D hw:1,0; kill %1
Linux richardiv 3.9.0-rc7-nextframe #8 SMP Fri Apr 19 16:29:37 PDT 2013 x86_64 GNU/Linux
[1] 4598
Playing raw data 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
ffff880154aba440 3793290194 S Co:4:005:0 s 01 0b 0001 0001 0000 0
ffff880154aba440 3793292190 C Co:4:005:0 0 0
ffff8801515a20c0 3793292289 S Co:4:005:0 s 22 01 0100 0001 0003 3 = 44ac00
ffff8801515a20c0 3793293167 C Co:4:005:0 0 3 >
ffff8801515a20c0 3793293206 S Ci:4:005:0 s a2 81 0100 0001 0003 3 <
ffff8801515a20c0 3793294188 C Ci:4:005:0 0 3 = 44ac00
ffff880142054dc0 3793294216 S Zo:4:005:1 -115:1:0 1 -18:0:176 176 = 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffff8801420541c0 3793294221 S Zo:4:005:1 -115:1:0 1 -18:0:176 176 = 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffff880142054dc0 3793305177 C Zo:4:005:1 0:1:362330:0 1 0:0:176 176 >
ffff880142054dc0 3793305202 S Zo:4:005:1 -115:1:362330 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793306165 C Zo:4:005:1 0:1:362331:0 1 0:0:176 176 >
ffff8801420541c0 3793306186 S Zo:4:005:1 -115:1:362331 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793307191 C Zo:4:005:1 0:1:362332:0 1 0:0:176 176 >
ffff880142054dc0 3793307208 S Zo:4:005:1 -115:1:362332 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793308190 C Zo:4:005:1 0:1:362333:0 1 0:0:176 176 >
ffff8801420541c0 3793308203 S Zo:4:005:1 -115:1:362333 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793309191 C Zo:4:005:1 0:1:362334:0 1 0:0:176 176 >
ffff880142054dc0 3793309209 S Zo:4:005:1 -115:1:362334 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793310194 C Zo:4:005:1 0:1:362335:0 1 0:0:176 176 >
ffff8801420541c0 3793310211 S Zo:4:005:1 -115:1:362335 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793311192 C Zo:4:005:1 0:1:362336:0 1 0:0:176 176 >
ffff880142054dc0 3793311211 S Zo:4:005:1 -115:1:362336 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793312194 C Zo:4:005:1 0:1:362337:0 1 0:0:176 176 >
ffff8801420541c0 3793312212 S Zo:4:005:1 -115:1:362337 1 -18:0:180 180 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793313172 C Zo:4:005:1 0:1:362338:0 1 0:0:176 176 >
ffff880142054dc0 3793313188 S Zo:4:005:1 -115:1:362338 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793314192 C Zo:4:005:1 0:1:362339:0 1 0:0:180 180 >
ffff8801420541c0 3793314209 S Zo:4:005:1 -115:1:362339 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793315192 C Zo:4:005:1 0:1:362340:0 1 0:0:176 176 >
ffff880142054dc0 3793315210 S Zo:4:005:1 -115:1:362340 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793316192 C Zo:4:005:1 0:1:362341:0 1 0:0:176 176 >
ffff8801420541c0 3793316209 S Zo:4:005:1 -115:1:362341 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793317196 C Zo:4:005:1 0:1:362342:0 1 0:0:176 176 >
ffff880142054dc0 3793317207 S Zo:4:005:1 -115:1:362342 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793318191 C Zo:4:005:1 0:1:362343:0 1 0:0:176 176 >
ffff8801420541c0 3793318209 S Zo:4:005:1 -115:1:362343 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793319193 C Zo:4:005:1 0:1:362344:0 1 0:0:176 176 >
ffff880142054dc0 3793319211 S Zo:4:005:1 -115:1:362344 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793320191 C Zo:4:005:1 0:1:362345:0 1 0:0:176 176 >
ffff8801420541c0 3793320208 S Zo:4:005:1 -115:1:362345 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793321196 C Zo:4:005:1 0:1:362346:0 1 0:0:176 176 >
ffff880142054dc0 3793321213 S Zo:4:005:1 -115:1:362346 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793322191 C Zo:4:005:1 0:1:362347:0 1 0:0:176 176 >
ffff8801420541c0 3793322208 S Zo:4:005:1 -115:1:362347 1 -18:0:180 180 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793323193 C Zo:4:005:1 0:1:362348:0 1 0:0:176 176 >
ffff880142054dc0 3793323210 S Zo:4:005:1 -115:1:362348 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793324191 C Zo:4:005:1 0:1:362349:0 1 0:0:180 180 >
ffff8801420541c0 3793324208 S Zo:4:005:1 -115:1:362349 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793325196 C Zo:4:005:1 0:1:362350:0 1 0:0:176 176 >
ffff880142054dc0 3793325213 S Zo:4:005:1 -115:1:362350 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793326192 C Zo:4:005:1 0:1:362351:0 1 0:0:176 176 >
ffff8801420541c0 3793326209 S Zo:4:005:1 -115:1:362351 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793327196 C Zo:4:005:1 0:1:362352:0 1 0:0:176 176 >
ffff880142054dc0 3793327216 S Zo:4:005:1 -115:1:362352 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff8801420541c0 3793328190 C Zo:4:005:1 0:1:362353:0 1 0:0:176 176 >
ffff8801420541c0 3793328220 S Zo:4:005:1 -115:1:362353 1 -18:0:176 176 = 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff 00ff00ff
ffff880142054dc0 3793329165 C Zo:4:005:1 -104:1:362354:0 1 0:0:176 176 >
ffff8801420541c0 3793330191 C Zo:4:005:1 0:1:362355:0 1 0:0:176 176 >
ffff880154ae6c80 3793333265 S Co:4:005:0 s 01 0b 0000 0001 0000 0
ffff880154ae6c80 3793335191 C Co:4:005:0 0 0
root at richardiv:~# 

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