Workaround xrandr bug: "cannot find crtc for output"

[johannish]

Disable all displays before attempting to call xrandr. This one-liner is probably very inefficient and exposes my inexperience with bash scripting. Feel free to modify the idea.

This is a workaround for an xrandr issue when two displays are connected and attempting to configure a different display, even when "off" is passed on the connected displays. See: https://bugs.freedesktop.org/show_bug.cgi?id=22539 and https://bugs.freedesktop.org/show_bug.cgi?id=29929

For example,

$ xrandr --output DP-1 --auto --output DP-2 --auto`
$ xrandr --output DP-1 --off --output DP-2 --off --output LVDS-1 --auto
# This will fail with error "cannot find crtc for output ..."

The workaround for this second command is instead to do:

xrandr --output DP-1 --off --output DP-2 --off && xrandr --output LVDS-1 --auto