drm/crtc-helper: Fixup error handling in drm_helper_crtc_mode_set

danvet · danvet · commit ce14ec20a1ff · 2015-07-03T09:15:50.000+02:00
In commit 9f658b7 Author: Daniel Stone <daniels@collabora.com> Date: Fri May 22 13:34:45 2015 +0100 drm/crtc_helper: Replace open-coded CRTC state helpers error handling code was broken, resulting in the first path not being checked correctly. Fix this by using the same pattern as in the transitional plane helper function drm_plane_helper_update. v2: Simplify the cleanup code while at it too. v3: After some debugging with John we realized that the above patch from Daniel also accidentally removed the if (crtc_state) check. This is legal when transitioning to atomic, when the initial state reset isn't all wired up yet properly. Reinstate that check to fix the bug John has hit. Cc: Daniel Stone <daniels@collabora.com> CC: Sean Paul <seanpaul@chromium.org> Cc: John Hunter <zhaojunwang@pku.edu.cn> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Reviewed-by: Daniel Stone <daniels@collabora.com> Reported-and-tested-by: John Hunter <zhaojunwang@pku.edu.cn> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
@@ -927,15 +927,13 @@ int drm_helper_crtc_mode_set(struct drm_crtc *crtc, struct drm_display_mode *mod
 
 	if (crtc->funcs->atomic_duplicate_state)
 		crtc_state = crtc->funcs->atomic_duplicate_state(crtc);
-	else {
+	else if (crtc->state)
+		crtc_state = drm_atomic_helper_crtc_duplicate_state(crtc);
+	else
 		crtc_state = kzalloc(sizeof(*crtc_state), GFP_KERNEL);
-		if (!crtc_state)
-			return -ENOMEM;
-		if (crtc->state)
-			__drm_atomic_helper_crtc_duplicate_state(crtc, crtc_state);
-		else
-			crtc_state->crtc = crtc;
-	}
+
+	if (!crtc_state)
+		return -ENOMEM;
 
 	crtc_state->planes_changed = true;
 	crtc_state->mode_changed = true;
@@ -957,11 +955,11 @@ int drm_helper_crtc_mode_set(struct drm_crtc *crtc, struct drm_display_mode *mod
 	ret = drm_helper_crtc_mode_set_base(crtc, x, y, old_fb);
 
 out:
-	if (crtc->funcs->atomic_destroy_state)
-		crtc->funcs->atomic_destroy_state(crtc, crtc_state);
-	else {
-		__drm_atomic_helper_crtc_destroy_state(crtc, crtc_state);
-		kfree(crtc_state);
+	if (crtc_state) {
+		if (crtc->funcs->atomic_destroy_state)
+			crtc->funcs->atomic_destroy_state(crtc, crtc_state);
+		else
+			drm_atomic_helper_crtc_destroy_state(crtc, crtc_state);
 	}
 
 	return ret;
