Hello,
I try to operate an old scanner on the parallel port for some small tasks.
I need to give rw permissions on /dev/parport0 for everyone, which I
achieved by changing the appropriate line in file
/etc/udev/static_devices.txt from
parport0 c 99 0 660
to
parport0 c 99 0 666
After reboot, the device had the permissions as expected:
ls -l /dev/parport*
crw-rw-rw- 1 root root 99, 0 2006-03-09 15:30 /dev/parport0
crw-rw-rw- 1 root root 99, 1 2006-03-09 15:30 /dev/parport1
crw-rw-rw- 1 root root 99, 2 2006-03-09 15:30 /dev/parport2
crw-rw-rw- 1 root root 99, 3 2006-03-09 15:30 /dev/parport3
However, starting xsane failed (with error-message "No devices
detected"). Checking again the permissions on /dev/parport returned:
crw-rw---- 1 root root 99, 0 2006-03-09 15:30 /dev/parport0
crw-rw-rw- 1 root root 99, 1 2006-03-09 15:30 /dev/parport1
crw-rw-rw- 1 root root 99, 2 2006-03-09 15:30 /dev/parport2
crw-rw-rw- 1 root root 99, 3 2006-03-09 15:30 /dev/parport3
The rw-permissions on parport0 have disappeared for everyone !!
chmod 666 /dev/parport0 brings back the permissions, which allows me
this time to start xsane and to operate the scanner.
Does anybody have an idea why xsane changes the permissions on
/dev/parport0 and , even more important, how to make it permanent? Btw.,
commands like SANE_DEBUG_MUSTEK_PP=128 scanimage -L also change the
permissions, so I guess that it's scanimage or sane-find-scanner that
affect the permissions when xsane uses them while probing for scanners.
Thanks for your input.
JJ Mouris