I didn't know about the SLI breakage, my bad.
Just did a clean install and I can confirm that it's working as it should:
$ xrandr --listproviders Providers: number : 2 Provider 0: id: 0x65 cap: 0x9, Source Output, Sink Offload crtcs: 3 outputs: 3 associated providers: 1 name:modesetting Provider 1: id: 0x3f cap: 0x4, Source Offload crtcs: 0 outputs: 0 associated providers: 1 name:nouveau
# cat /sys/kernel/debug/vgaswitcheroo/switch 0:IGD:+:Pwr:0000:00:02.0 1:DIS: :Off:0000:01:00.0
I didn't know about the SLI breakage, my bad.
Just did a clean install and I can confirm that it's working as it should:
$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x65 cap: 0x9, Source Output, Sink Offload crtcs: 3 outputs: 3 associated providers: 1 name:modesetting
Provider 1: id: 0x3f cap: 0x4, Source Offload crtcs: 0 outputs: 0 associated providers: 1 name:nouveau
# cat /sys/kernel/ debug/vgaswitch eroo/switch :Pwr:0000: 00:02.0
0:IGD:+
1:DIS: :Off:0000:01:00.0