drm/nouveau: Check dsm on switcheroo unregister

Currently vga_switcheroo_unregister_handler is called unconditionally when
nouveau is unloaded, even when nouveau never registered a handler. This
interferes with other switcheroo handlers, as vga_switcheroo doesn't check who
called unregister_handler, but simply unregisters the current handler. This
patch adds a check so unregister is only called if a handler was registered by
nouveau before.

Signed-off-by: Andreas Heider <andreas@meetr.de>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index 284bd25d5d2127a3d44f9d8efae7449b77edcfbd..fc841e87b343a6aa71cc05bb7f4ae94e7399fafc 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -338,7 +338,8 @@ void nouveau_switcheroo_optimus_dsm(void)
 
 void nouveau_unregister_dsm_handler(void)
 {
-       vga_switcheroo_unregister_handler();
+       if (nouveau_dsm_priv.optimus_detected || nouveau_dsm_priv.dsm_detected)
+               vga_switcheroo_unregister_handler();
 }
 
 /* retrieve the ROM in 4k blocks */