drm/udl: drop drm_driver.release hook

There's only two functions called from that:
drm_kms_helper_poll_fini() and udl_free_urb_list(). Both of these are
also called from the ubs_driver->disconnect hook, so entirely
pointless to do the same again in the ->release hook.

Furthermore by the time we clean up the drm_driver we really shouldn't
be touching hardware anymore, so stopping the poll worker and freeing
the urb allocations in ->disconnect is the right thing to do.

Now disconnect still cleans things up before unregistering the driver,
but that's a different issue.

v2: Use _fini, not _disable in unplug, motivated by discussions with
Thomas. _disable/_enable are for suspend/resume.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-51-daniel.vetter@ffwll.ch

drivers/gpu/drm/udl/udl_drv.c

@@ -34,14 +34,8 @@ static int udl_usb_resume(struct usb_interface *interface)
 
 DEFINE_DRM_GEM_FOPS(udl_driver_fops);
 
-static void udl_driver_release(struct drm_device *dev)
-{
-	udl_fini(dev);
-}
-
 static struct drm_driver driver = {
 	.driver_features = DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
-	.release = udl_driver_release,
 
 	/* gem hooks */
 	.gem_create_object = udl_driver_gem_create_object,
@@ -120,7 +114,7 @@ static void udl_usb_disconnect(struct usb_interface *interface)
 {
 	struct drm_device *dev = usb_get_intfdata(interface);
 
-	drm_kms_helper_poll_disable(dev);
+	drm_kms_helper_poll_fini(dev);
 	udl_drop_usb(dev);
 	drm_dev_unplug(dev);
 	drm_dev_put(dev);

drivers/gpu/drm/udl/udl_drv.h

@@ -76,7 +76,6 @@ int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
 void udl_urb_completion(struct urb *urb);
 
 int udl_init(struct udl_device *udl);
-void udl_fini(struct drm_device *dev);
 
 int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,
 		     const char *front, char **urb_buf_ptr,

drivers/gpu/drm/udl/udl_main.c

@@ -351,13 +351,3 @@ int udl_drop_usb(struct drm_device *dev)
 	udl_free_urb_list(dev);
 	return 0;
 }
-
-void udl_fini(struct drm_device *dev)
-{
-	struct udl_device *udl = to_udl(dev);
-
-	drm_kms_helper_poll_fini(dev);
-
-	if (udl->urbs.count)
-		udl_free_urb_list(dev);
-}