About 6 months ago, I successfully installed my Epson-902a printer/scanner following the instructions in https://kaosx.us/docs/print/
I don't use the printer very often, so I cannot say exactly when it stopped working. I noticed after upgrading the system this morning. The output from sudo pacman -Syu included the following warning:

warning: directory permissions differ on /var/cache/cups/
filesystem: 770 package: 775`

When attempting to print a pdf from Okular, the print job is listed in the Print Queue but marked as "stopped"
The same happens if I try printing the test page from System Settings.

I have checked the hardware. I booted another Linux distro and the printer worked OK.

Is the warning about permissions on /var/cache/cups/ relevant to this problem, and if so what exactly should I do about it. If the warning isn't relevant, what else could be causing the printer to not work in KaOS?

Did you have to create a udev rule to make the printer work initially? (see https://kaosx.us/docs/print/#troubleshooting). Is that rule still available?
Also check the printer logs, see if they show the issue. They are in /var/log/cups

Yes, I did have to create a udev rule. I checked and the rule is still there.

In the log it says:

E [09/Nov/2017:11:25:31 +0900] [Job 14] The PPD version (5.2.12) is not compatible with Gutenprint 5.2.13.  Please run `/usr/sbin/cups-genppdupdate\' as administrator.

So I navigated to /usr/sbin/ in Dolphin, right-clicked to get root actions, and opened /usr/sbin/ as root. I then left-clicked on cups-genppdupdate and executed. (This seems a laborious way to execute a script as admininstrator, but I couldn't find a simpler way.) Now the printer works again.

KaOS is great!

  • demm replied to this.

    DCBX (This seems a laborious way to execute a script as admininstrator, but I couldn't find a simpler way.)

    Since you are the administrator, no need for any extra steps. If ever needed again, just run cups-genppdupdate in krunner, konsole or yakuake.