drm/omap: fix the handling of fb ref counts

With the recent primary-plane changes for drm, the primary plane's
framebuffer needs to be ref counted the same way as for
non-primary-planes. This was not done by the omapdrm driver, which
caused the ref count to drop to 0 too early, causing problems.

This patch moves the fb unref and ref from omap_plane_update to
omap_plane_mode_set. This way the fb refs are updated for both primary
and non-primary cases, as omap_plane_update calls omap_plane_mode_set.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/omap_plane.c

@@ -225,6 +225,11 @@ int omap_plane_mode_set(struct drm_plane *plane,
 		omap_plane->apply_done_cb.arg = arg;
 	}
 
+	if (plane->fb)
+		drm_framebuffer_unreference(plane->fb);
+
+	drm_framebuffer_reference(fb);
+
 	plane->fb = fb;
 	plane->crtc = crtc;
 
@@ -241,11 +246,6 @@ static int omap_plane_update(struct drm_plane *plane,
 	struct omap_plane *omap_plane = to_omap_plane(plane);
 	omap_plane->enabled = true;
 
-	if (plane->fb)
-		drm_framebuffer_unreference(plane->fb);
-
-	drm_framebuffer_reference(fb);
-
 	/* omap_plane_mode_set() takes adjusted src */
 	switch (omap_plane->win.rotation & 0xf) {
 	case BIT(DRM_ROTATE_90):