Hello, for some time I was using configuration like this :
Option "metamodes" "CRT-0: 1152x864_120 +0+0, DFP-1: NULL; CRT-0: 1152x864_120 +0+0, DFP-1: 1920x1080_60 +1152+0"
In all the 290 series drivers, Xorg started in pure 1152x864 mode with second display disabled.
Starting with 302 and continuing up to 313, Xorg starts:
- with only the CRT enabled, in 1152x864 mode (as it should)
- but the desktop is in a 3720x1080 virtual mode with panning (that’s unusual).
Turns out, if I enter only one metamode:
Option "metamodes" "CRT-0: 1152x864_120 +0+0, DFP-1: NULL"
This will make the 300+ drivers do what I want.
This doesn’t stop nvidia-settings and/or disper from enabling dual-head modes later on, so I can live with that.
As minor as it seems, it is an incompatibility and probably a bug, so I’m posting here for others who might google for this problem after upgrading.
 Actually, I was using nvidia-auto-select for the second display, but it stopped working in one of the 300 ones. I was also using modes named 1152x864@120 (with an "@") but that was also broken by one of the 300 ones :)