I confirm, when you delete the nouveau.runpm=0 option from grub (no need to force the -1 value if you just modify the grub file, it's default if @nepenthes is right), you get :
sudo cat /sys/kernel/debug/vgaswitcheroo/switch
0:IGD:+:Pwr:0000:00:02.0 1:DIS: :DynOff:0000:01:00.0
I confirm, when you delete the nouveau.runpm=0 option from grub (no need to force the -1 value if you just modify the grub file, it's default if @nepenthes is right), you get :
sudo cat /sys/kernel/ debug/vgaswitch eroo/switch
0:IGD:+ :Pwr:0000: 00:02.0 0000:01: 00.0
1:DIS: :DynOff: