[Intel-gfx] [PATCH 3/7] drm/atomic-helper: add sync_all helper for gpu reset

[Daniel Vetter]

i915 needs this.

Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_atomic_helper.c | 38 +++++++++++++++++++++++++++++++++++++
 include/drm/drm_atomic_helper.h     |  1 +
 2 files changed, 39 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index cea610161af5..545328a9a769 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1763,6 +1763,44 @@ static struct drm_crtc_commit *preceeding_commit(struct drm_crtc *crtc)
 }
 
 /**
+ * drm_atomic_helper_sync_all - synchronize with all pending nonblocking commits
+ * @dev: DRM device
+ *
+ * This function synchronizes with all pending atomic commits using the
+ * nonblocking helpers (see drm_atomic_helper_setup_commit()) up to the point
+ * where all hardware commits are completed (as signalled using
+ * drm_atomic_helper_commit_hw_done().
+ *
+ * This is useful you need to synchronize with all nonblocking comits, but do
+ * not want to or cannot do a full atomic commit touching all CRTC. All CRTC
+ * looks must be held to prevent a concurrent thread from queuing yet another
+ * update. Drivers can use this for e.g. their gpu reset handling, when a gpu
+ * reset also affects the display block.
+ */
+void drm_atomic_helper_sync_all(struct drm_device *dev)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_commit *commit;
+
+	drm_for_each_crtc(crtc, dev) {
+		spin_lock(&crtc->commit_lock);
+		commit = list_first_entry_or_null(&crtc->commit_list,
+				struct drm_crtc_commit, commit_entry);
+		if (commit)
+			drm_crtc_commit_get(commit);
+		spin_unlock(&crtc->commit_lock);
+
+		if (!commit)
+			continue;
+
+		wait_for_completion(&commit->hw_done);
+
+		drm_crtc_commit_put(commit);
+	}
+}
+EXPORT_SYMBOL(drm_atomic_helper_sync_all);
+
+/**
  * drm_atomic_helper_wait_for_dependencies - wait for required preceeding commits
  * @old_state: atomic state object with old state structures
  *
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index ed90d0c5ba09..95bef7c3632f 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -92,6 +92,7 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
 /* nonblocking commit helpers */
 int drm_atomic_helper_setup_commit(struct drm_atomic_state *state,
 				   bool nonblock);
+void drm_atomic_helper_sync_all(struct drm_device *dev);
 void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *state);
 void drm_atomic_helper_commit_hw_done(struct drm_atomic_state *state);
 void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *state);
-- 
2.13.2