My scanner (Canoscan N676U) suddenly stopped responding when I upgraded to Ubuntu Feisty. I first noticed the problem when I was unable to import a scan through Gimp. Well it took a couple hours to figure this one out, but the sollution turned out to be easy to implement. From what I understand, the problem comes from the USB suspend functions built into the new kernel. I also understand that this isn’t just an Ubuntu problem. So if you are on another distro, this tip may work for you also.

Download and install scanbuttond which is a daemon that allows you to invoke actions such as shell scripts whenever one of the scanner front panel buttons is pressed. I do not use my scanners buttons, and this tip will work even if your scanner doesn’t have any buttons. The daemon periodically polls the scanner helping to prevent it from suspending and becoming unresponsive. So start up a terminal and…

sudo apt-get install scanbuttond
scanbuttond -r 1000000

The 1000000 is the number of microseconds between polls to the scanner. So the scanbuttond deamon will poll your scanner once per second. If you are finished with your scanning, and want to stop the scanbuttond daemon from polling your scanner, simply stop the daemon.

killall scanbuttond