[Bug 920937] Something lets CUPS backend "usb" sometimes no longer detect USB printers on openSUSE Tumbleweed (worked on openSUSE 13.2)
http://bugzilla.suse.com/show_bug.cgi?id=920937
http://bugzilla.suse.com/show_bug.cgi?id=920937#c135
--- Comment #135 from Ian Powell
Only FYI regarding scanner device node setup via udev:
"rw-rw-r-- root lp" for a USB scanner device node happens via /etc/udev/rules.d/55-libsane.rules (from sane-backends RPM) and for scanners in HP all-in-one devices additionally via /usr/lib/udev/rules.d/56-hpmud.rules (from the hplip RPM).
Both set ENV{libsane_matched}="yes" and that one triggers in /usr/lib/udev/rules.d/70-uaccess.rules (from the systemd RPM) that TAG+="uaccess" is set which triggers in /usr/lib/udev/rules.d/73-seat-late.rules (from the systemd RPM) to RUN{builtin}+="uaccess" that manages device node user ACLs which finally results the '+' in "rw-rw-r--+" (i.e. an ACL setting) for a USB scanner device node.
To display the ACL run as root # getfacl /dev/bus/usb/
/ The ACL is only set when a normal user logs in directly at the computer (not from remote). In this case that normal user gets read/write access for the USB scanner device node.
For example on my Tumblewed system where I am directly logged in as normal user "johannes": ---------------------------------------------------------------------------- # lsusb ... Bus 004 Device 003: ID 04a9:220e Canon, Inc. CanoScan N1240U/LiDE 30
# ls -l /dev/bus/usb/004/003 crw-rw-r--+ 1 root lp 189, 386 Jul 21 14:36 /dev/bus/usb/004/003
# getfacl /dev/bus/usb/004/003 getfacl: Removing leading '/' from absolute path names # file: dev/bus/usb/004/003 # owner: root # group: lp user::rw- user:johannes:rw- group::rw- mask::rw- other::r-- ----------------------------------------------------------------------------
Regardless that I can sometimes show how it usually should work I cannot really help when something with udev or systemd does not work as it should because I am not at all a sufficient expert to debug or even fix issues that are related to udev or systemd.
thanks. you know a lot more that me and i'm grateful for the info I'm just happy now that everything happens to work as it should -- You are receiving this mail because: You are on the CC list for the bug.
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