Re: [LAU] UA-101

Colin Fletcher wrote: USB high speed uses 8000 frames per second, so one packet contains about 5.5 (44100/8000) samples. It's obvious that the USB packets are exchanged somehow. Please try the patch below, or download the new ua101.c from <http://www.alsa-project.org/~clemens/ua101.c>. This will log the sequence in which the first 50 USB packets are received, but it won't fix anything. Since the kernel crash happens when resetting the capture interface, there is a possibilty that these bugs are related, probably due to some corruption of the EHCI data structures. Trying a 2.6.33 kernel might help, although I don't know of any change that could affect this. Regards, Clemens --- alsa-kernel/sound/usb/ua101.c.orig Tue Feb 16 21:47:56 2010 +++ alsa-kernel/sound/usb/ua101.c Wed Feb 24 13:28:57 2010 @@ -367,6 +367,14 @@ unsigned int frames, write_ptr; bool do_period_elapsed; int err; + static int ccc = 0; + + if (ccc < 50) { + ccc++; + for (err = 0; err < stream->queue_length; ++err) + if (urb == &stream->urbs[err]->urb) + printk(KERN_DEBUG "completed URB %d\n", err); + } if (unlikely(urb->status == -ENOENT || /* unlinked */ urb->status == -ENODEV || /* device removed */ @@ -465,6 +473,8 @@ err, usb_error_string(err)); return err; } + if (stream == &ua->capture) + printk(KERN_DEBUG "submitted URB %u\n", i); } return 0; }