How do I resolve "xrandr: cannot find crtc for output"?

This occurs becaues you have another screen already active, in this case DP2. DP2 here is a monitor running off of a DisplayPort. The laptop is a Lenovo x230 and it was booted with an Ultrabase 3 docking station.

You can resolve this issue by simply turning off the screen using,

xrandr --output DP2 --off

Now, in XFCE or similar workstation you should see your desktop area shrink. Then you can continue running your xrandr commands as you normally would,

xrandr --auto
xrandr ...