Hi all, I have a HiDPI laptop display (3200x1800) and a "normal" external LCD (1680x1050). For a while now I've worked around the DPI mismatch by scaling the external LCD:
/usr/bin/xrandr --auto --output eDP-1 --mode 3200x1800 --left-of DP-1 --output DP-1 --mode 1680x1050 --scale 2x2 (ie create a very large virtual framebuffer, and scale down the part which ends up on the external monitor output.) With xorg 1.19.6 (& earlier) and the modesetting driver this seemed to work. I see the following line in Xorg.0.log when I run the command: (II) modeset(0): Allocate new frame buffer 6560x2100 stride With xorg 1.20 it no longer works. I get an error line in the log and the external display ends up in a weird state: [ 793.006] (II) modeset(0): Allocate new frame buffer 6560x2100 stride [ 793.090] failed to add rotate fb If I use --scale 1x1 in the same xrandr command, everything works as expected. Maybe using --scale 2x2 is "doing it wrong" and I need to find a better way, but I thought I'd mention this in case it's a bug or something I can work around. Some additional notes: * Graphics card is Intel HD520, i915 kernel driver, kernel 4.16.11 * Full Xorg.log attached here: https://pastebin.com/raw/piWQZvfg Around timestamp 793 you can see me trying a few variations on the xrandr command, including a few which work. * I'm running the Arch Linux xorg-server package. I looked at the Arch patchset and it's very close to upstream, couldn't see anything patched in the vicinity of the modesetting driver. But I haven't tried building upstream xorg myself, yet. Thanks for any sage advice you can provide, Angus _______________________________________________ [email protected]: X.Org support Archives: http://lists.freedesktop.org/archives/xorg Info: https://lists.x.org/mailman/listinfo/xorg Your subscription address: %(user_address)s
