[PATCH RFC v2 2/2] drm/atomic: Disable planes on blanked CRTC and enable on unblank

[Jyri Sarha]

Disable planes if they are on to be blanked CRTC and enable them when
the CRTC is turned back on by DMPS.

This is desirable on HW that loses its context on blanking. When
planes are enabled and disabled with the associated CRTCs, there is no
need to restore the plane context in runtime_resume callback.

Signed-off-by: Jyri Sarha <jsarha at ti.com>
---
 drivers/gpu/drm/drm_atomic_helper.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index d03e2ac..5cd8016 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2027,8 +2027,8 @@ EXPORT_SYMBOL(drm_atomic_helper_page_flip);
  *
  * This is the main helper function provided by the atomic helper framework for
  * implementing the legacy DPMS connector interface. It computes the new desired
- * ->active state for the corresponding CRTC (if the connector is enabled) and
- *  updates it.
+ * ->active state for the corresponding CRTC and planes on it (if the connector
+ * is enabled) and updates it.
  *
  * Returns:
  * Returns 0 on success, negative errno numbers on failure.
@@ -2041,6 +2041,7 @@ int drm_atomic_helper_connector_dpms(struct drm_connector *connector,
 	struct drm_crtc_state *crtc_state;
 	struct drm_crtc *crtc;
 	struct drm_connector *tmp_connector;
+	struct drm_plane *tmp_plane;
 	int ret;
 	bool active = false;
 	int old_mode = connector->dpms;
@@ -2079,6 +2080,20 @@ retry:
 	}
 	crtc_state->active = active;
 
+	/* Collect associated plane states to global state object. */
+	list_for_each_entry(tmp_plane, &config->plane_list, head) {
+		struct drm_plane_state *plane_state;
+
+		if (tmp_plane->state->crtc != crtc)
+			continue;
+
+		plane_state = drm_atomic_get_plane_state(state, tmp_plane);
+		if (IS_ERR(plane_state)) {
+			ret = PTR_ERR(plane_state);
+			goto fail;
+		}
+	}
+
 	ret = drm_atomic_commit(state);
 	if (ret != 0)
 		goto fail;
-- 
1.9.1