drm/nouveau/falcon: avoid touching registers if engine is off

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108980Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/engine/falcon.c

@@ -22,6 +22,7 @@
 #include <engine/falcon.h>
 
 #include <core/gpuobj.h>
+#include <subdev/mc.h>
 #include <subdev/timer.h>
 #include <engine/fifo.h>
 
@@ -107,8 +108,10 @@ nvkm_falcon_fini(struct nvkm_engine *engine, bool suspend)
 		}
 	}
 
-	nvkm_mask(device, base + 0x048, 0x00000003, 0x00000000);
-	nvkm_wr32(device, base + 0x014, 0xffffffff);
+	if (nvkm_mc_enabled(device, engine->subdev.index)) {
+		nvkm_mask(device, base + 0x048, 0x00000003, 0x00000000);
+		nvkm_wr32(device, base + 0x014, 0xffffffff);
+	}
 	return 0;
 }