I am currently running KDE NEON 5.20 with nvidia drivers 390. I am using a laptop and a second VGA samsung monitor. My problem is that sometimes (after waking up from sleep or turning on) my second monitor will be detected as only DP-1 (usually as samsung monitor) and with a maximum resolution of 1024x768 instead of the usual 1366x768. Generally I was able to just restart and it would go back to detecting the monitor correctly, but this time I am completely stuck.
Another strange thing that is happening is that the notifications are on do not disturb mode upon initial login due to the screens being mirrored. This usually wasn't the case when the resolution and monitor was correctly detected.
Things I've tried:
> adding a manual modeline via xrandr: did not work, I could not make a 1366x768 work with xrandr, it would always mess the real resolution to something smaller

The monitor functions perfectly while on Windows and I've never had similar issues, so I don't think this is related to hardware.
This has been happening for a few releases now, and I don't know what causes this and what can fix it.

Any help will be much appreciated.

An update to this: going back to windows and rebooting back to KDE NEON makes my monitor be detected correctly again. Still somewhat cumbersome and not a decent fix.

Hi,
Command and values for a 1366x768 (60 Hz) in xrandr:
xrandr --newmode "1366x768_60.00" 85.25 1366 1440 1576 1784 768 771 781 798 -hsync +vsync
To add mode to your monitor (change my value 'VGA-1' with your device's name):
xrandr --output VGA-1 --mode "1366x768_60.00"

joninchaurbe wrote:Hi,
Command and values for a 1366x768 (60 Hz) in xrandr:
xrandr --newmode "1366x768_60.00" 85.25 1366 1440 1576 1784 768 771 781 798 -hsync +vsync
To add mode to your monitor (change my value 'VGA-1' with your device's name):
xrandr --output VGA-1 --mode "1366x768_60.00"

Thanks for the input, but this is simply does not display correctly. I'm not trying to get it to work correctly again to get the modeline, but I haven't had any luck yet.