drm/vmwgfx: Disable damage clipping if FB changed since last page-flip

The driver does per-buffer uploads and needs to force a full plane update
if the plane's attached framebuffer has change since the last page-flip.
Suggested-by: Sima Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Acked-by: Sima Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20231123221315.3579454-4-javierm@redhat.com

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

@@ -832,10 +832,21 @@ int vmw_du_primary_plane_atomic_check(struct drm_plane *plane,
 {
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state,
 									   plane);
+	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
+									   plane);
 	struct drm_crtc_state *crtc_state = NULL;
 	struct drm_framebuffer *new_fb = new_state->fb;
+	struct drm_framebuffer *old_fb = old_state->fb;
 	int ret;
 
+	/*
+	 * Ignore damage clips if the framebuffer attached to the plane's state
+	 * has changed since the last plane update (page-flip). In this case, a
+	 * full plane update should happen because uploads are done per-buffer.
+	 */
+	if (old_fb != new_fb)
+		new_state->ignore_damage_clips = true;
+
 	if (new_state->crtc)
 		crtc_state = drm_atomic_get_new_crtc_state(state,
 							   new_state->crtc);