Parallel port scanners
Scanning over my parallel port scanner does not work unless my user is in the "lp" group. This article says that users need not be in any special group for the scanner to work since systemd.
Basically, my experience contradicts the article and I would like to either fix my setup or the article so both are in agreement.
- I wasn't aware that parallel port scanners were a thing!
- SANE#Permission problem is really only relevant for usb scanners - parallel ports are assumed to have printers attached, and CUPS uses the
lpgroup for other purposes. See FS#50009, and the note in CUPS#Connection Interfaces. The short version is that the wiki should be fixed to mention this and that you adding your user to the lp group is perfectly fine unless you are concerned about your user being able to view some of the CUPS files, which may contain sensitive information such as network printer passwords.
- -- Pypi (talk) 00:46, 19 June 2017 (UTC)
- I've made an edit to the page - does that fix the article for you? -- Pypi (talk) 01:25, 19 June 2017 (UTC)
I think the fix discussed above with “lp” udev group can also help with USB multi-function printers/scanners. My understanding of the problem is: a single device can not be owned by multiple groups in udev. So as soon as you add the rule with GROUP=“scanner”, printing may stop working. It’s kind of random, sometimes it works, so I spent a lot of time debugging it.
The solution for me was to use GROUP=“cups” in the scanner rule mentioned in SANE#Permission problem. I tried to edit the page, but my edit was reverted. Maybe someone could phrase it better than me.