https://bugzilla.kernel.org/show_bug.cgi?id=84431
--- Comment #7 from Pali Rohár pali.rohar@gmail.com --- Function vga_switcheroo_init_domain_pm_optimus_hdmi_audio() is used in sound/pci/hda/hda_intel.c. So that driver has same problem and cause kernel panic on driver unload.