On Fri, 6 Dec 2002 09:54:44 +1100 Nick Croft wrote: > Any ideas on what is needed to make /dev/usbscanner permanent? After > a reboot, it seems I need to do > > sudo mknod /dev/usbscanner c 180 48 > sudo chmod 666 /dev/usbscanner > > > each time.
Sounds like you're running with devfs. Does a "ps ax" show a devfsd process running? I wasn't aware that distributions were turning it on by default.. The Documentation/usb/scanner.txt file in your kernel source tree has details on how to make devfs do what you want, ie something like: REGISTER ^usb/scanner0$ CFUNCTION GLOBAL symlink usb/scanner0 usbscanner UNREGISTER ^usb/scanner0$ CFUNCTION GLOBAL unlink usbscanner in /etc/devfsd.conf (or /etc/devfs/devfsd.conf on some distributions), and killall -HUP devfsd to reload the configuration. And to set the same permissions you'll need a line like REGISTER ^usb/scanner.$ PERMISSIONS root.root 0666 (untested, YMMV, etc...) > And in a similar area, when I list /dev/usb, I get > > nick@artarmon ~ % ls /dev/usb -l > total 0 > crw-rw-rw- 1 root root 180, 48 Jan 1 1970 > scanner0 Yep, definitely devfs. It's a dynamic filesystem, and device nodes are created and deleted on the fly by the kernel as modules are loaded and unloaded (or in the case of USB, as devices are added or removed). The default naming scheme is wildly different to what you're used to, though, and it's the job of the devfsd daemon to add symlinks to the more familiar device names. It also manages ownership and permissions of devices. The point is that everything created by devfs gets an epoch timestamp. > And strangely, root is not allowed to rm that device, according to the > means known to me. (I seem to recall making that one some time agao > when I was trying to configure an unsupported scanner). Another side effect of the dynamic generation. By the same token, you can't remove anything in /proc either, although it could be a pretty neat way to upgrade or replace broken hardware. The kernel documentation again has fairly thorough devfs documentation, in Documentation/filesystems/devfs/ . Also see the manpages for devfsd and devfsd.conf. Cheers, -- Pete -- SLUG - Sydney Linux User's Group - http://slug.org.au/ More Info: http://lists.slug.org.au/listinfo/slug
