disabling discrete nVidia GPU

I wonder if it's any possible to do on OpenBSD? looking at the bbswitch
source code, seems like these are the only commands that run when you do
'echo OFF >> /proc/acpi/bbswitch'

pci_save_state(dis_dev);
pci_clear_master(dis_dev);
pci_disable_device(dis_dev);
pci_set_power_state(dis_dev, PCI_D3cold);

and I see similar functions on /sys/dev/pci/pci.c

int pcidetach(struct device *, int);
void pci_powerdown(struct pci_softc *);
int pci_set_powerstate(pci_chipset_tag_t pc, pcitag_t tag, int state)