struct vga_switcheroo_client_ops — client callbacks
struct vga_switcheroo_client_ops {
void (* set_gpu_state) (struct pci_dev *dev, enum vga_switcheroo_state);
void (* reprobe) (struct pci_dev *dev);
bool (* can_switch) (struct pci_dev *dev);
}; do the equivalent of suspend/resume for the card. Mandatory. This should not cut power to the discrete GPU, which is the job of the handler
poll outputs. Optional. This gets called after waking the GPU and switching the outputs to it
check if the device is in a position to switch now. Mandatory. The client should return false if a user space process has one of its device files open