xrandr fails to change virtual-screen size when required
Submitted by Eric S. Raymond
Assigned to Keith Packard @keithp
Description
Encountered when configuring a Radeon HD7750 dual-head card to drive two Auria 2650x1440 displays, but the problem is clearly more generic than that.
These monitors began in Same mode. xrandr refused a command to map them side-by-side, explaining that virtual size 5120x1440 was required but the virtual size in place was 2650x2650.
Working around this required writing a custom xorg.conf. And I have to ask: why?
Why doesn't xrandr simply compute the bounding box for any specified layout and set the virtual screen size accordingly? Why require this pointless ceremony of manual setting?