snd-usb-usx2y (Tascam US-122) sequence errors

[Dr Nicholas J Bailey <nicholas.bailey@glasgow.ac.uk>]

I'm on debian jessie,

Linux arial 3.10-3-686-pae #1 SMP Debian 3.10.11-1 (2013-09-10) i686 GNU/Linux

with a Tascam us-122 that has recently stopped working.

When I try to capture with anything, there is a few hundred ms of audio then 
the capture process stalls and the following dmesg appears:

[  462.596296] Sequence Error!(hcd_frame=0 ep=8in;wait=1024,frame=0).
[  462.596296] Most probably some urb of usb-frame 1024 is still missing.
[  462.596296] Cause could be too long delays in usb-hcd interrupt handling.
[  477.959230] Sequence Error!(hcd_frame=0 ep=8in;wait=1024,frame=0).
[  477.959230] Most probably some urb of usb-frame 1024 is still missing.
[  477.959230] Cause could be too long delays in usb-hcd interrupt handling.

Before this kernel, the box worked OK. The only think that leads me to believe 
it might be my fault is that for a very long time, I've had to plug the box 
in:

[  445.529271] usb 2-1.6: new full-speed USB device number 5 using ehci-pci
[  445.622076] usb 2-1.6: New USB device found, idVendor=1604, idProduct=8006
[  445.622086] usb 2-1.6: New USB device strings: Mfr=0, Product=0, 
SerialNumber=0

then unplug it and plug it in again:

[  445.972743] usb 2-1.6: USB disconnect, device number 5
[  447.621519] usb 2-1.6: new full-speed USB device number 6 using ehci-pci
[  447.714462] usb 2-1.6: New USB device found, idVendor=1604, idProduct=8007
[  447.714471] usb 2-1.6: New USB device strings: Mfr=0, Product=0, 
SerialNumber=0
[  447.834852] usbcore: registered new interface driver snd-usb-usx2y
[  455.194314] usb 2-1.6: USB disconnect, device number 6
[  457.487433] usb 2-1.6: new full-speed USB device number 7 using ehci-pci
[  457.579960] usb 2-1.6: New USB device found, idVendor=1604, idProduct=8006
[  457.579969] usb 2-1.6: New USB device strings: Mfr=0, Product=0, 
SerialNumber=0

to get the firmware to load

[  457.888884] usb 2-1.6: USB disconnect, device number 7
[  459.379782] usb 2-1.6: new full-speed USB device number 8 using ehci-pci
[  459.472516] usb 2-1.6: New USB device found, idVendor=1604, idProduct=8007
[  459.472526] usb 2-1.6: New USB device strings: Mfr=0, Product=0, 
SerialNumber=0

(green USB light comes on here).

I'm not sure about how to start debugging this; there are many things that 
could be wrong. If it will help, I'll try and file a bug report; if not please 
tell me to shut up (prefereably after pointing me at the solution :) )

Nick/.