[pvrusb2] My tuners occasionally get stuck

[Jan Ceuleers]

Hi there.

I have four HVR 1900s connected to a Zotac H55 ITX motherboard running 
Ubuntu 11.04 with kernel 2.6.38-13-generic x86_64. This machine is used 
as a Mythtv master backend.

Occasionally the tuners get stuck, producing zero-length recordings. 
When this happens, messages like the following show up in the kernel log:

Mar 11 07:44:18 zotac kernel: [295057.966383] usb 1-4: clear tt 1 (8050) 
error -110
Mar 11 07:44:38 zotac kernel: [295077.954410] usb 1-4: clear tt 1 (8050) 
error -110
Mar 11 07:44:48 zotac kernel: [295087.928496] usb 1-4: clear tt 1 (8050) 
error -110
Mar 11 07:45:08 zotac kernel: [295107.886686] usb 1-4: clear tt 1 (8050) 
error -110
Mar 11 07:45:28 zotac kernel: [295127.824858] usb 1-4: clear tt 1 (8050) 
error -110
Mar 11 07:45:48 zotac kernel: [295147.772971] usb 1-4: clear tt 1 (8050) 
error -110

In order to recover I need to power down the tuners. Simply rebooting 
the server is not enough.

If I don't attend to this problem quickly enough, the machine's USB 
connectivity becomes entirely unusable. For example: my APC UPS becomes 
incommunicado.

Does anyone have any idea as to how to begin debugging this?

Thanks, Jan