how do I allow console access to a scanner connected via USB/libusb?
After reboot the scanner can be found by sane-find-scanner but cannot be used because the device file in /proc/bus/usb is only accessible to root. How can I automatically change ownership of this device *without* depending on the bus#/device# scheme used in /proc/bus/usb?
Try to locate the entry for your scanner in the sysfs hierarchy as described at: http://www.reactivated.net/udevrules.php (look in the "Identifying devices through SYSFS files" section). You should be able to identify a section that mentions the manufacturer and model number of your scanner.
You can then add a udev rule that will create a symlink /dev/scannerN to the correct device entry for your scanner when it is plugged in, by creating a file /etc/udev/rules.d/10-custom.rules that matches your scanner. For example, I have an HP ScanJet 3c, and the rule I use is:
BUS="scsi", SYSFS{vendor}="HP*", SYSFS{model}="C2520A*", SYMLINK="scanner%n"Although my scanner is SCSI, the principle should be the same. Just change the BUS, SYSFS{vendor} and SYSFS{model} to match your device.
Since the symlink created is called /dev/scannerN (where N is probably 0), the existing set of console rules should cause the device ownership to be set to the console logged-in user without any further changes.
Paul.
