Udev rule to create /dev/scanner

For some unknown reason, Kubuntu 8.04 doesn’t create a /dev/scanner link while it’s figuring out all the SCSI devices. I wanted to make the link sort of generic for any scanner that I might plug in, but I had to settle for a unique udev match.

The scanner popped out of udev as /dev/sg5 this time and

udevinfo --query=all --attribute-walk --name=/dev/sg5

emits this useful chunk:

looking at parent device '/devices/pci0000:00/0000:00:1e.0/0000:05:05.0/host4/target4:0:2/4:0:2:0':
    KERNELS=="4:0:2:0"
    SUBSYSTEMS=="scsi"
    DRIVERS==""
    ATTRS{device_blocked}=="0"
    ATTRS{type}=="3"
    ATTRS{scsi_level}=="3"
    ATTRS{vendor}=="HP      "
    ATTRS{model}=="C7670A          "
    ATTRS{rev}=="3945"
    ATTRS{state}=="running"
    ATTRS{timeout}=="0"
    ATTRS{iocounterbits}=="32"
    ATTRS{iorequest_cnt}=="0x656"
    ATTRS{iodone_cnt}=="0x656"
    ATTRS{ioerr_cnt}=="0x2"
    ATTRS{modalias}=="scsi:t-0x03"
    ATTRS{evt_media_change}=="0"
    ATTRS{queue_depth}=="2"
    ATTRS{queue_type}=="none"

Plucking the readable bits out produces this stanza for/etc/udev/rules.d/60-symlinks.rules

#-- hack to create /dev/scanner
SUBSYSTEMS=="scsi", ATTRS{vendor}=="HP", ATTRS{model}=="C7670A", SYMLINK+="scanner"

Then you can use that to fire up xsane thusly:

sane hp:/dev/scanner

With that in hand, edit GIMP’s ~/.gimp-whatever/menurc and ~/.gimp-whatever/pluginrc to replace sg5 (or whatever) with scanner.

Works like a champ…

The straight dope on writing udev rules is at http://www.reactivated.net/writing_udev_rules.html

Memo to self: there’s got to be a way to make this generic, perhaps by piggybacking on whatever udev stanza assigns the scanner group to that /dev/sg? device.

Update: make sure you’re in the scanner group

sudo usermod -a -G scanner username