Other display related things I’ve found which may be of use:
- Use VGA and DVI but not HDMI :
I have one monitor connected to the vga out on the video card - never had any problems on that.
The other was on the card’s hdmi out. There’s also a kvm (keyb/video/mouse) switch in the middle to muddy the diagnosis waters.
I was getting screen blacking out occasionally - most days for a while in the afternoons usually - on the hdmi monitor only.
There was talk online about it being related to the hdmi audio.
I couldn’t find any of the settings they were talking about and don’t currently have the time to look into what my system is using for audio - possible complications from the fact I have Gnome and KDE stuff installed etc - so for a possible quick fix I got a DVI-to-HDMI cable (£3.76 new on ebay) and put the hdmi monitor on the card’s DVI out and have had no screen problems since.
- Screen alignment
When I first switched from HDMI to DVI the monitor’s image was slighlty off and none of the “auto adjust” options were available. So there was a gap in my extended desktop where the 2 monitor images “meet”.
I manged to fix/clear this by changing both monitors to the highest resolution available on both that was just below the resolution of the lower one so where I have
Monitor1: 1680x1050
Monitor2: 1440x900
I changed both to 1280x1024 where the alignment corrected itself and then back to their original resolutions where they all remained correctly aligned and no issues with that since.
- Diplay managers
I’m not having any issues with the standard Display Manager(s). I updated an issue with my install notes for KDE here :
- Login loop
I had what sounds like the same problem as you “…Secret Password, it comes back and asks you for it again and again” a while back.
Alas I don’t seem to have made any notes on how I fixed it…but I do now recall having to get selinux to relabel everything as part of fixing stuff and it would make sense that an selinux denial during login would send you back.
To fix it I had to do the emergency target thing at boot to access the file system (you could also boot from an alt OS on a usb drive and mount the filesystem) and then
create the file /.autorelabel and reboot. I may have done touch /.autorelable if it was already there. But you should see the system being relabeled during the next boot.
- Nvidia problems ?
My original nvidia issues - mostly solved by switching to a radeon may in part have been hdmi related but I’m not going to look into that just yet.
- KDE multi monitor desktop problem
Sometimes when I login, 1 monitor is black (no wallpaper) and does not respond to right clicks but is otherwise usable. When this happens the other monitor will have 2 wallpaper images overlapped.
You can restart KDE plasmashell without logging out/losing your workspace state and this will clear that problem - similar to restarting Windows explorer when it gets confused.
kquitapp5 plasmashell || killall plasmashell && kstart5 plasmashell
from kwin - Can I restart the KDE Plasma Desktop without logging out? - Ask Ubuntu
- Mallets
For persistent offenders a taser may be more effective: short,sharp,shock,they won’t do it again.