Scaling high DPI displays (Xorg)

kyescott · 2022-05-15 04:47:22

I recently installed Arch using the new install script, and I selected Qtile for the tiling window manager. I've got my high DPI laptop display to work using xrandr and to scale the UI appropriately. I also have a 1440p monitor that I connect to via display port, and I have also gotten that to work using the --above flag of xrandr and I've got this setup to automatically detect when I connect to it using autorandr. However, the scaling on the second monitor is obnoxiously large. If I attempt to reduce the scaling using the --scale flag of xrandr, then I get weird issues where part of my laptop display overlaps with part of the second monitor display and there are black boxes on the right hand side of the displays.

I'm really new to Arch (moved from Linux Mint), and I'm excited to learn! Any advice for scaling the second monitor display would be appreciated. Please let me know what information would be helpful.

Thanks!

seth · 2022-05-15 06:00:18

https://wiki.archlinux.org/title/HiDPI# … e_displays
This isn't an arch or mint thing.
Qt is pretty much the only toolkit that's somewhat per-output DPI aware, https://wiki.archlinux.org/title/HiDPI#Qt_5

kyescott · 2022-05-15 22:54:54

Fair enough. I'll keep tinkering with the position and see if I can get something usable. So is the default recommendation just not to use a high DPI second display? Is there some way to emulate what Linux Mint is able to do by default (some package or something)?

seth · 2022-05-16 05:24:56

Idk what Mint does by default (notably because this will depend on the clients) or whether it maybe actually defaults to a wayland display server (which effectively all do output scaling, except they scale the clients), but there're various strategies mentioned in the linked wiki.
#1 run the HiDPI output at a lower resolution
#2 scale one of the outputs w/ xrandr (preferably the low-res one up)
#3 pick intermittent DPI and client scaling factors (ie. ones that are too small for the HiDPI and too big for the other display but kinda work on both)

If I attempt to reduce the scaling using the --scale flag of xrandr, then I get weird issues where part of my laptop display overlaps with part of the second monitor display and there are black boxes on the right hand side of the displays.

If this is going to be the preferred attempt, please post the output of "xrandr -q" before and after that attempt as well as the exact xrandr command you tried.

Arch Linux

#1 2022-05-15 04:47:22

Scaling high DPI displays (Xorg)

#2 2022-05-15 06:00:18

Re: Scaling high DPI displays (Xorg)

#3 2022-05-15 22:54:54

Re: Scaling high DPI displays (Xorg)

#4 2022-05-16 05:24:56

Re: Scaling high DPI displays (Xorg)

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