[mythtv-users] FYI - HDPVR in a KVM VM possible using usbip service

Matt Mossholder matt at mossholder.com
Sun Oct 9 23:13:53 UTC 2011

Hey everyone,
     I wanted to pass along something I figured out today, that might
help someone else. I moved my HDPVR-1212 off of my frontend, and to my
backend, which runs as a VM via KVM. I initially used the USB
passthrough functionality of KVM to connect the device to the VM. THis
didn't work out so well... I would only get 2-4 seconds of video
before polling of the device would begin to fail. Even just cat'ing to
a file didn't work for more than 2-4 seconds.

     Then I ran across the usbip package available in Ubuntu Natty
(unsure on other releases, and unable to locate it for Fedora in a
quick search). This package lets you specify a USB device to share on
one system, and attach it to a virtual USB controller on another.

     Basically, all I needed to do on the server was run `modprobe
usbip; modprobe usbip_common_mod; usbipd -D; usbip_bind_device --usbip
1-2`, where 1-2 is the Bus id of the device given by
`usbip_bind_device --list`. On the client it was just `modprobe
vhci_hcd; usbip -a 192.168.XXX.XXX 1-2`.

     Surprisingly, it actually worked. MythTV detected the shared USB
device, and is recording without any glitches in the first 10 minutes
or so of testing. Load on both systems remained low, with the virtual
USB rx/tx system taking about 8% of CPU in the backend VM, and about
2% in the native server.

     Not bad for something so crazy :)


P.S. I used this HOWTO to get things working:

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