drm: Use plane->state->fb over plane->fb

Stop looking at plane->fb on atomic drivers. Use plane->state->fb
instead.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180322152313.6561-9-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/drm_atomic_helper.c

@@ -2670,7 +2670,7 @@ int drm_atomic_helper_disable_plane(struct drm_plane *plane,
 		goto fail;
 	}
 
-	if (plane_state->crtc && (plane == plane->crtc->cursor))
+	if (plane_state->crtc && plane_state->crtc->cursor == plane)
 		plane_state->state->legacy_cursor_update = true;
 
 	ret = __drm_atomic_helper_disable_plane(plane, plane_state);

drivers/gpu/drm/drm_crtc.c

@@ -597,13 +597,20 @@ retry:
 		/* If we have a mode we need a framebuffer. */
 		/* If we pass -1, set the mode with the currently bound fb */
 		if (crtc_req->fb_id == -1) {
-			if (!plane->fb) {
+			struct drm_framebuffer *old_fb;
+
+			if (plane->state)
+				old_fb = plane->state->fb;
+			else
+				old_fb = plane->fb;
+
+			if (!old_fb) {
 				DRM_DEBUG_KMS("CRTC doesn't have current FB\n");
 				ret = -EINVAL;
 				goto out;
 			}
 
-			fb = plane->fb;
+			fb = old_fb;
 			/* Make refcounting symmetric with the lookup path. */
 			drm_framebuffer_get(fb);
 		} else {

drivers/gpu/drm/drm_plane.c

@@ -792,7 +792,11 @@ static int drm_mode_cursor_universal(struct drm_crtc *crtc,
 			fb = NULL;
 		}
 	} else {
-		fb = plane->fb;
+		if (plane->state)
+			fb = plane->state->fb;
+		else
+			fb = plane->fb;
+
 		if (fb)
 			drm_framebuffer_get(fb);
 	}
@@ -934,7 +938,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 	struct drm_mode_crtc_page_flip_target *page_flip = data;
 	struct drm_crtc *crtc;
 	struct drm_plane *plane;
-	struct drm_framebuffer *fb = NULL;
+	struct drm_framebuffer *fb = NULL, *old_fb;
 	struct drm_pending_vblank_event *e = NULL;
 	u32 target_vblank = page_flip->sequence;
 	struct drm_modeset_acquire_ctx ctx;
@@ -1012,7 +1016,12 @@ retry:
 	if (ret)
 		goto out;
 
-	if (plane->fb == NULL) {
+	if (plane->state)
+		old_fb = plane->state->fb;
+	else
+		old_fb = plane->fb;
+
+	if (old_fb == NULL) {
 		/* The framebuffer is currently unbound, presumably
 		 * due to a hotplug event, that userspace has not
 		 * yet discovered.
@@ -1027,7 +1036,7 @@ retry:
 		goto out;
 	}
 
-	if (crtc->state) {
+	if (plane->state) {
 		const struct drm_plane_state *state = plane->state;
 
 		ret = drm_framebuffer_check_src_coords(state->src_x,
@@ -1042,7 +1051,7 @@ retry:
 	if (ret)
 		goto out;
 
-	if (plane->fb->format != fb->format) {
+	if (old_fb->format != fb->format) {
 		DRM_DEBUG_KMS("Page flip is not allowed to change frame buffer format.\n");
 		ret = -EINVAL;
 		goto out;