drm/atomic: Remove waits in drm_atomic_helper_commit_cleanup_done, v2.

When commit synchronization through drm_crtc_commit was first
introduced, we tried to solve the problem of the flip_done
needing a reference count by blocking in cleanup_done.

This has been changed by commit 24835e442f28 ("drm: reference count
event->completion") which made the waits here no longer needed.

However, even after this commit we still needed the wait because
otherwise we cannot wait for the flip_done because this item might
have been removed from the list.

Changed since v1:
- Make mention of cleanup_done completing before flip_done.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170904104838.23822-4-maarten.lankhorst@linux.intel.com

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 075b0b3..8bc2f15 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1872,7 +1872,6 @@ void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *old_state)
        struct drm_crtc_state *old_crtc_state;
        struct drm_crtc_commit *commit;
        int i;
-       long ret;
 
        for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
                commit = old_crtc_state->commit;
@@ -1882,22 +1881,6 @@ void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *old_state)
                complete_all(&commit->cleanup_done);
                WARN_ON(!try_wait_for_completion(&commit->hw_done));
 
-               /* commit_list borrows our reference, need to remove before we
-                * clean up our drm_atomic_state. But only after it actually
-                * completed, otherwise subsequent commits won't stall properly. */
-               if (try_wait_for_completion(&commit->flip_done))
-                       goto del_commit;
-
-               /* We must wait for the vblank event to signal our completion
-                * before releasing our reference, since the vblank work does
-                * not hold a reference of its own. */
-               ret = wait_for_completion_timeout(&commit->flip_done,
-                                                 10*HZ);
-               if (ret == 0)
-                       DRM_ERROR("[CRTC:%d:%s] flip_done timed out\n",
-                                 crtc->base.id, crtc->name);
-
-del_commit:
                spin_lock(&crtc->commit_lock);
                list_del(&commit->commit_entry);
                spin_unlock(&crtc->commit_lock);