Recent Framework 16 Laptop purchaser, and things were going great as I loaded it up with Arch-based Manjaro KDE plasma on my table… I brought a DP monitor over and set the KDE settings with the DP monitor set on the left of the laptop. No problems other than the SSDM issue I raised/resolved in Use of USB port on GPU Expansion Module - #27 by Daniel_I
Once all my tweaks were made and a couple steam games were happy, I moved the laptop over to my desk, and placed the same DP monitor on the right… updated KDE settings to this fact, and launched a game.
I’m not quite sure how to explain this, but the game launched (windowed as expected) spanning the two monitors… I thought not much about it, and dragged it over to the right so it was on the DP monitor… and then things started acting weird. It was like an invisible vertical line existed about 1/4 way in from the left side of my DP monitor… any part of the game window beyond that invisible line was not refreshed/redrawn (like an snapshot/picture)… nor were any mouse clicks recognized.
Basically, this is what I think is happening… possibly KDE or X11 is remembering the old position of the game (and/or old position/orientation/size of the displays) when the 2560x1440 DP monitor was on the left. When the game loads, it looks spanned because it’s starting the game on the current left monitor (now the laptop) with a lesser 1680x1050 resolution… so when it draws the window out it spans over to the second monitor to retain the window size.
Why the “invisible line” exists where the mouse can’t click and the frames don’t update… really has me confused. It’s like it knows, this is where the right edge of 2560x1440 ends on the total screen, and because the DP monitor is on the right now (no screen beyond it), whatever happens passed this edge is no mans land.
When i launched the second game (fullscreen as expected) it loaded on the left monitor (laptop); perfectly fine, just not the DP monitor. Hit alt-Enter to swap the game into a window, dragged it over to the right onto my DP monitor, and was unable to select anything in the game’s menu because the game’s cursor refused t move beyond the “invisible line”.
Then I got curious… what if I swapped the position of the monitors in KDE’s settings? Well, when I do that, both games launch fine, no invisible lines, and no freeze-frame areas… even if I drag the windowed game between the monitors. This can be my work-around, but I know not being able to cross the mouse smoothly between them “normally” will get annoying quickly.
I don’t think it’s anything “cached” or an erroneous config within my HOME directory as I created a fresh test account that duplicated the issue.
I should also point out the contents of the /usr/share/sddm/scripts/Xsetup
edits I’d made in the link provided above changed when I swapped the DP to the right of the laptop…
#!/bin/sh
# Xsetup - run as root before the login dialog appears
xrandr --output DisplayPort-1-0 --mode 2560x1440 --primary
xrandr --output eDP-1 --mode 1680x1050 --left-of DisplayPort-1-0 --noprimary
And to rule out this as the issue, I’ve tested with the xrandr lines removed as well.
I’ve also tried with and without DRI_PRIME=1 %command%
in the steam game’s launch options, but the end result is the same.