Если включить в конфигурацию второй Screen, то второй монитор работает (приглашение gdm ввести пароль), но после попытки залогиниться, gdm рестартует. С одним Screen (любым из двух) такой проблемы нет.
gdm-session-worker[2239]: pam_unix(gdm:session): session opened for user doctor by (uid=0)
gdm-session-worker[2239]: pam_ck_connector(gdm:session): nox11 mode, ignoring PAM_TTY :0
gnome-keyring-daemon[2256]: dbus failure unregistering from session: Connection is closed
gnome-keyring-daemon[2256]: dbus failure unregistering from session: Connection is closed
gdm-session-worker[2239]: pam_unix(gdm:session): session closed for user doctor
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0" 0 0
Screen 1 "Screen1" 0 0
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"
EndSection
Section "Device"
Identifier "Device0"
Driver "intel"
VendorName "Intel Corporation"
BusID "PCI:00:02:0"
EndSection
Section "Device"
Identifier "Device1"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BusID "PCI:01:00:0"
EndSection