Re: [LAD] Trying to fix the Edirol UA-101

Hi, I'm working toward getting the UA-101 to work on Linux. I've had a look at the Alsa drivers, and I after 23s of playback I hit the known glitch bug:

http://lists.linuxaudio.org/pipermail/linux-audio-user/2009-April/059447.ht… I've tried fiddling with various alsa buffering settings to get a point solution that works, but with no luck. Comparing the USB traffic on Windows and Linux was interesting. The Linux trace has the sound samples being sent to USB Endpoint 2, but the Windows trace is weird. The both traces the sound sample was a long period of silence followed by a sine wave. There are several things 'odd' under windows: The data send to the sound card (on USB EP 2) started out as as string of '0x00 0x00...' as you would expect for a 'silence' sample. After about 2 seconds, 'silence' is send as lots blocks like 00000000: 00 00 ff ff 00 ff fe ff 00 ff ff ff 00 ff ff ff 00000010: 00 00 00 00 00 ff ff ff 00 00 00 00 00 ff ff ff in a pattern I haven't got to the bottom of yet. The second difference I've noticed is that on Windows the UA-101 is sending data to the PC (on USB EP 81). This is 'random' data (but it does have a lot of zeros in it), I haven't investigated it yet: 00000000: 00 a9 fb ff 00 e5 00 00 00 65 00 00 00 11 00 00 00000010: 00 5c 00 00 00 15 00 00 00 3f 00 00 00 f9 ff ff 5760 bytes are sent to the sound card, then 9120 bytes are sent back. This cycle repeats every ~4.6ms. That is about 26 bytes/sample out and 41 bytes/sample back. I'll take some more accurate measurements when I have a parser for the log format. On Linux there is no data being read back. My next move is going to construct some .wav files that differ in a few samples and compare the traces that they produce. I have a couple of questions: * Does anyone know the background behind "I think that's the mentioned synchronizing-problem in the UA-1000 quirk ('FIXME: playback must be synchronized to capture')"? * Any idea what could be causing the glitch? * Has anyone done any analysis on this problem before? Cheers, Phil _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev(a)lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev