Rayudu Addagarla wrote: > Hello > When i run scanimage -L as user i dont see the devices. > when i run as root i can see the devices. > i set Debug on and i see plustek backend says open failed. > > sane-find-scanner gives that device is libusb:001:002 > The permission on the /proc/bus/usb/001/002 device file has read > permissions to everyone. > -rw-r--r-- 1 root root 43 2005-08-29 17:42 002 > > I had to change to have write permissions to other like, > -r--r--rw- 1 root root 57 2005-08-30 12:22 002 > then only as user i can see the device with scanimage -L > > Is this a common behavior? I expect to have only read perms and does not > require write perms. > > My system configuration: > SuSE , Version = 9.1 > sane-frontends-1.0.13-2 > xsane-gimp-0.95-3 > sane-backends-1.0.15-9 > xsane-0.95-3
You usually need both read and write permission on the /proc/bus/usb device files to access a scanner. For example, a backend probably needs to send scan settings to the scanner before starting a scan and this requires write permission. This may even be the case for positively identifying the scanner. By default, kernel 2.6 sets the permission quite restrictive. As far as I know, distros solve this by using a hotplug script that updates the permission for the /proc/bus/usb files to r/w for a group called 'scanner' or 'usb'. Any user who wants to access the scanner needs to be a member of this group. So perhaps the hotplug script is not working properly on your PC. Bertrik
