The point of testing on a different computer is to try and narrow down the location of the problem. If the problem persists then it's likely to be in the USB device. Otherwise it's likely to be in the computer's hardware or software.
I just realized that my own USB audio device uses asynchronous mode. (The lsusb output is attached so you can see for yourselves.) Unlike Tyson's device it supports only 16-bit audio, not 24-bit, but like his, it runs at full speed. And the usbmon output I get from it looks quite similar to the posted traces. However my device works just fine, no crackling noises or anything when running at 44100 samples/second. So more testing is needed. Here's the next thing to try. This will require a kernel that was built with CONFIG_USB_DEBUG enabled. Go to the appropriate subdirectory of /sys/kernel/debug/usb/ehci/. On Tyson's system that would be the 0000:00:1a.0 directory (because the EHCI controller for bus 1 is named 0000:00:1a.0). While the crackly audio is playing make a copy of the "periodic" file, and then attach the copy to this bug report. It would be great also to see the same thing for a kernel that doesn't have the troublesome commit. ** Attachment added: "lsusb output for my USB audio device" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1136110/+attachment/3655259/+files/lsusb -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1136110 Title: USB Audio Codec choppy playback To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1136110/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
