drm: Reject mode set with current fb if no current fb is bound

When doing a mode set with the special fb id -1, reject the mode set if
no fb is currently bound to the crtc.

Also remove the pointless list traversal to find the current crtc based
on the current crtc :)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 6fdaf6fe94eb57dfcc36c6c23a454c1ca8519d80..bbcecdb4e0ad4171cfc3b32997a0984c32c9d8a5 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1755,7 +1755,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
        struct drm_mode_config *config = &dev->mode_config;
        struct drm_mode_crtc *crtc_req = data;
        struct drm_mode_object *obj;
-       struct drm_crtc *crtc, *crtcfb;
+       struct drm_crtc *crtc;
        struct drm_connector **connector_set = NULL, *connector;
        struct drm_framebuffer *fb = NULL;
        struct drm_display_mode *mode = NULL;
@@ -1782,14 +1782,12 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
                /* 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) {
-                       list_for_each_entry(crtcfb,
-                                           &dev->mode_config.crtc_list, head) {
-                               if (crtcfb == crtc) {
-                                       DRM_DEBUG_KMS("Using current fb for "
-                                                       "setmode\n");
-                                       fb = crtc->fb;
-                               }
+                       if (!crtc->fb) {
+                               DRM_DEBUG_KMS("CRTC doesn't have current FB\n");
+                               ret = -EINVAL;
+                               goto out;
                        }
+                       fb = crtc->fb;
                } else {
                        obj = drm_mode_object_find(dev, crtc_req->fb_id,
                                                   DRM_MODE_OBJECT_FB);