drm/nouveau: populate master subdev pointer only when fully constructed

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/core/subdev.c

@@ -104,11 +104,8 @@ nouveau_subdev_create_(struct nouveau_object *parent,
 
 	if (parent) {
 		struct nouveau_device *device = nv_device(parent);
-		int subidx = nv_hclass(subdev) & 0xff;
-
 		subdev->debug = nouveau_dbgopt(device->dbgopt, subname);
 		subdev->mmio  = nv_subdev(device)->mmio;
-		device->subdev[subidx] = *pobject;
 	}
 
 	return 0;

drivers/gpu/drm/nouveau/core/engine/device/base.c

@@ -268,6 +268,8 @@ nouveau_devobj_ctor(struct nouveau_object *parent,
 		if (ret)
 			return ret;
 
+		device->subdev[i] = devobj->subdev[i];
+
 		/* note: can't init *any* subdevs until devinit has been run
 		 * due to not knowing exactly what the vbios init tables will
 		 * mess with.  devinit also can't be run until all of its

drivers/gpu/drm/nouveau/core/include/subdev/fb.h

@@ -75,6 +75,11 @@ struct nouveau_fb {
 static inline struct nouveau_fb *
 nouveau_fb(void *obj)
 {
+	/* fbram uses this before device subdev pointer is valid */
+	if (nv_iclass(obj, NV_SUBDEV_CLASS) &&
+	    nv_subidx(obj) == NVDEV_SUBDEV_FB)
+		return obj;
+
 	return (void *)nv_device(obj)->subdev[NVDEV_SUBDEV_FB];
 }