Whenever I try to print anything to /dev/lp0 (the parallel port of my ASUS M5A78L-M LE mainboard), my Ubuntu 20.04 server freezes completely (display gets black, no keyboard input, no network reaction). Thereby it doesn't matter whether I try printing a testpage in the webinterface of CUPS (http://localhost:631), trying to print a Windows 10 test page from a SaMBa client or try entering 'echo "Test" > /dev/lp0' on the console. When trying the latter, my HP LaserJet 6L printer prints 'Te', so a little bit of the print job seams to come out before the crash. In /var/log/syslog, there are no entries about the crash (I tried waiting 5 minutes, then do the echo test, then wait another 5 minutes before restarting to be able to isolate any possible entries caused by the crash clearly by the time stamp, but there aren't any).
As a workaround, I installed a DELOCK 90413 'Serial + Parallel PCI Express x1 Card' into my server, which is recognized as /dev/lp1. When using this parallel port, printing works perfectly.
In my old hardware with another mainboard, the same installation (I just changed hard disks) worked perfectly with the internal /dev/lp0. I also tried printing to the problematic parallel port on my new server hardware (the problematic one) using FreeDOS 1.3, just to confirm that my hardware is not defective, and it worked perfectly.
So Ubuntu 20.04 seems to have a problem with the internal parallel port of the ASUS M5A78L-M LE mainboard. Unfortunately, I cannot tell which package is affected as I can't find any log entries. However, I guess, it's not cups, as a direct echo to /dev/lp0 also does not work. So I guess, it's something deeper.
What you also need:
1) Ubuntu 20.04.3 LTS
2) I don'd know. Sorry.
3) When printing to /dev/lp0, a page should come out of the printer.
4) When printing to /dev/lp0, the whole system crashed (display black, no reaction to anything).
If I can provide you further information to fix this bug, please don't hesitate to contact me. However, you need to help me how to gather it, as all my ideas are already described above.
Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https:/
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