[PATCH] drm/atomic_helper: Add drm_atomic_helper_disable_planes_on_crtc()

[Jyri Sarha]

Add drm_atomic_helper_disable_planes_on_crtc() for disabling all
planes associated with the given CRTC. This can be used for instance
in the CRTC helper disable callback to disable all planes before
shutting down the display pipeline.

Signed-off-by: Jyri Sarha <jsarha at ti.com>
---
This a follow version to "[PATCH RFC] drm/crtc_helper: Add
drm_crtc_helper_disable_planes()"-patch [1], with Daniel Vetter's
review comments [2] implemented. Hope I got everything right this
time. Thanks a lot for the prompt review.

Best regards,
Jyri

[1] http://www.spinics.net/lists/dri-devel/msg94720.html
[2] http://www.spinics.net/lists/dri-devel/msg94722.html

 drivers/gpu/drm/drm_atomic_helper.c | 52 +++++++++++++++++++++++++++++++++++++
 include/drm/drm_atomic_helper.h     |  2 ++
 2 files changed, 54 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index a53ed7a..229c810 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1281,6 +1281,58 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev,
 EXPORT_SYMBOL(drm_atomic_helper_commit_planes);
 
 /**
+ * drm_atomic_helper_disable_planes_on_crtc - helper to disable CRTC's planes
+ * @crtc: CRTC
+ * @atomic: if set, synchronize with CRTC's atomic_begin/flush hooks
+ *
+ * Disables all planes associated with the given CRTC. This can be
+ * used for instance in the CRTC helper disable callback to disable
+ * all planes before shutting down the display pipeline.
+ *
+ * If there are planes to disable and the atomic-parameter is set the
+ * function calls the CRTC's atomic_begin hook before and atomic_flush
+ * hook after disabling the planes.
+ *
+ * It is a bug to call this function without having implemented the
+ * ->atomic_disable() plane hook.
+ */
+void drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc *crtc,
+					      bool atomic)
+{
+	const struct drm_crtc_helper_funcs *crtc_funcs =
+		crtc->helper_private;
+	struct drm_plane *plane;
+	bool flush = false;
+
+	if (!crtc_funcs || !crtc_funcs->atomic_begin)
+		atomic = false;
+
+	drm_for_each_plane(plane, crtc->dev) {
+		const struct drm_plane_helper_funcs *plane_funcs =
+			plane->helper_private;
+
+		if (plane->state->crtc != crtc || !plane_funcs)
+			continue;
+
+		if (atomic && !flush) {
+			crtc_funcs->atomic_begin(crtc, NULL);
+			flush = true;
+		}
+
+		WARN_ON(!plane_funcs->atomic_disable);
+		if (plane_funcs->atomic_disable)
+			plane_funcs->atomic_disable(plane, NULL);
+	}
+
+	if (flush) {
+		WARN_ON(!crtc_funcs->atomic_flush);
+		if (crtc_funcs->atomic_flush)
+			crtc_funcs->atomic_flush(crtc, NULL);
+	}
+}
+EXPORT_SYMBOL(drm_atomic_helper_disable_planes_on_crtc);
+
+/**
  * drm_atomic_helper_commit_planes_on_crtc - commit plane state for a crtc
  * @old_crtc_state: atomic state object with the old crtc state
  *
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 8cba54a..b7d4237 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -62,6 +62,8 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev,
 void drm_atomic_helper_cleanup_planes(struct drm_device *dev,
 				      struct drm_atomic_state *old_state);
 void drm_atomic_helper_commit_planes_on_crtc(struct drm_crtc_state *old_crtc_state);
+void drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc *crtc,
+					      bool atomic);
 
 void drm_atomic_helper_swap_state(struct drm_device *dev,
 				  struct drm_atomic_state *state);
-- 
1.9.1