* Gerhard Jaeger <gerhard at gjaeger.de> [071206 15:50]: > On Thursday 06 December 2007 09:18:36 Johannes Ranke wrote: > > Hi Gerhard and Gerard, > > (replying to Gerard because I didn't receive Gerhards mail since I am > > not on the list) > > > > Thanks for the suggestion with CONFIG_USB_SUSPEND! I just booted a > > self-compiled kernel without this option, and scanning works again from > > the graphical frontends. What I don't understand is why it works from > > the command line with scanimage, but not with the graphical frontends. > > > > The GUI frontends are checking for the device and the release it. > This is the point, where the USB subsystem waits some time and decides > to go to the suspend mode - which the scanners don't like.
OK. > scanimage itself, opens the device and scans without giving the USB > subsystem the chance to go to sleep... > > AFAIK, there's a workaround in more recent kernels, but I don't > recall - maybe Julien? Yes, I just read in a long Ubuntu forum thread, that in more recent kernels, the possibility exists to exclude usb suspend to be active on certain devices via udev rules. Together with a new sane version this is supposed to fix the issue. > Another workaround came to my mind: use the scanbutton daemon, > which checks each 200ms for a pressed scanner button. That way, > the USB won't also fell asleep... Yes, I just saw that this workaround was mentioned in the forum thread to be working, too. I guess this is THE workaround if you have a working older kernel with CONFIG_USB_SUSPEND=y and don't want to upgrade. Thanks a lot for your explanations! Johannes > > Ciao, > Gerhard -- Dr. Johannes Ranke jranke at uni-bremen.de Key ID: F649AF90 UFT Bremen, Leobenerstr. 1 +49 421 218 63373 D-28359 Bremen http://www.uft.uni-bremen.de/chemie/ranke
