HOWTO: Make KDE remember dual-monitor randr settings

Every time I boot up, KDE appears to forget that I want my monitors to be positioned left-to-right and instead defaults to mirrored config. But, after a lot of cursing and a little googling, I found an answer so it'll no so much keep your settings, but reset its broken config to your settings.

1. Hit ALT-F2, then enter "display" to run the Display Settings app.

2. Configure your settings as you'd like. Note that if the Apply button isn't active after your changes, you can change/revert something like a Position: button to make it active.

3. On restart, KDE may forget your dual-monitor settings. So, to prevent this, go look in your ~/.kde/share/config/krandrrc file:

[Display]
ApplyOnStartup=true
StartupCommands=xrandr --output "DVI-I-1" --pos 1920x0 --mode 1920x1200 --refresh 59.9502\nxrandr --output "HDMI-1" --pos 0x130 --mode 1920x1080 --refresh 60\nxrandr --noprimary

4. Copy the configuration into a new file, and replace \n with newlines. I like to put scripts like this in /etc/X11 because they relate to screen res and positioning.

# from ~/.kde/share/config/krandrrc
xrandr --output "DVI-I-1" --pos 1920x0 --mode 1920x1200 --refresh 59.9502 
xrandr --output "HDMI-1" --pos 0x130 --mode 1920x1080 --refresh 60 
xrandr --noprimary

5. Ensure the script is readable/executable for all users:

chmod 755 /etc/X11/1920x2.sh

6. Hit ALT-F2, then enter "autostart" to run the Autostart config tool.

7. Click Add script... and browse for the script you created above.

8. Reboot and watch the magic unfold.

Switching monitors with xrandr

Sure, there are applets and other GUI tools to do this, but nothing beats the purity of going commando, er, commandline. :) Thanks to this article for the inspiration.

# reset 
xrandr --auto

# turn off laptop screen
xrandr --output LVDS --off

# 24" 16x12 on
xrandr --output VGA --mode 1600x1200

# reset 
xrandr --auto

# turn off external screen
xrandr --output VGA --off

# laptop screen on
xrandr --output LVDS --mode 1280x800

UPDATE, 2010/01/05:

To enable both screens and force the larger one to include the taskbar:

# reset 
xrandr --auto

# laptop screen on
xrandr --output LVDS1 --mode 1280x800 --noprimary --pos 1600x0

# 24" 16x12 on
xrandr --output VGA1 --mode 1600x1200 --primary --pos 0x0

# echo current status
xrandr --current