drm/crtc-helper: Fixup error handling in drm_helper_crtc_mode_set

In

commit 9f658b7b62e7aefc1ee067136126eca3f58cabfd
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
index 393114df88a3dbeb5326db27c7a16465fcf1550b..93104f3555f5fd0e8c44f9ece3038c158ac197a7 100644 (file)
--- 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;