drm/vmwgfx: Cursor update fixes

Use drm_plane_helper_check_update also for the cursor plane.
Some applications, like gdm on gnome shell still uses cursor front-buffer
like rendering without notifying the kernel. We do need some kind of
noficiation, but work around this for now by updating the cursor image on
every cursor move.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

@@ -393,13 +393,13 @@ vmw_du_cursor_plane_atomic_update(struct drm_plane *plane,
 	du->cursor_surface = vps->surf;
 	du->cursor_dmabuf = vps->dmabuf;
 
-	/* setup new image */
 	if (vps->surf) {
 		du->cursor_age = du->cursor_surface->snooper.age;
 
 		ret = vmw_cursor_update_image(dev_priv,
 					      vps->surf->snooper.image,
-					      64, 64, hotspot_x, hotspot_y);
+					      64, 64, hotspot_x,
+					      hotspot_y);
 	} else if (vps->dmabuf) {
 		ret = vmw_cursor_update_dmabuf(dev_priv, vps->dmabuf,
 					       plane->state->crtc_w,
@@ -497,11 +497,22 @@ int vmw_du_cursor_plane_atomic_check(struct drm_plane *plane,
 	struct vmw_surface *surface = NULL;
 	struct drm_framebuffer *fb = new_state->fb;
 
+	struct drm_rect src = drm_plane_state_src(new_state);
+	struct drm_rect dest = drm_plane_state_dest(new_state);
 
 	/* Turning off */
 	if (!fb)
 		return ret;
 
+	ret = drm_plane_helper_check_update(plane, new_state->crtc, fb,
+					    &src, &dest,
+					    DRM_MODE_ROTATE_0,
+					    DRM_PLANE_HELPER_NO_SCALING,
+					    DRM_PLANE_HELPER_NO_SCALING,
+					    true, true, &new_state->visible);
+	if (!ret)
+		return ret;
+
 	/* A lot of the code assumes this */
 	if (new_state->crtc_w != 64 || new_state->crtc_h != 64) {
 		DRM_ERROR("Invalid cursor dimensions (%d, %d)\n",