disp: msm: dsi: handle wait for dma cmd completion

The current solution triggers the DMA command and waits till
the command dma done and ISR signals completion. This change
introduces asynchronous wait after a DCS command has been
triggered. Enable this mode only during pre kickoff, so as to not
block commit thread.

Change-Id: Iead7b6328883e844147d47ff68dc878943879553
Signed-off-by: Satya Rama Aditya Pinapala <psraditya30@codeaurora.org>

msm/sde/sde_connector.c

@@ -759,6 +759,7 @@ int sde_connector_pre_kickoff(struct drm_connector *connector)
 	struct sde_connector *c_conn;
 	struct sde_connector_state *c_state;
 	struct msm_display_kickoff_params params;
+	struct dsi_display *display;
 	int rc;
 
 	if (!connector) {
@@ -773,6 +774,15 @@ int sde_connector_pre_kickoff(struct drm_connector *connector)
 		return -EINVAL;
 	}
 
+	/*
+	 * During pre kickoff DCS commands have to have an
+	 * asynchronous wait to avoid an unnecessary stall
+	 * in pre-kickoff. This flag must be reset at the
+	 * end of display pre-kickoff.
+	 */
+	display = (struct dsi_display *)c_conn->display;
+	display->queue_cmd_waits = true;
+
 	rc = _sde_connector_update_dirty_properties(connector);
 	if (rc) {
 		SDE_EVT32(connector->base.id, SDE_EVTLOG_ERROR);
@@ -789,6 +799,7 @@ int sde_connector_pre_kickoff(struct drm_connector *connector)
 
 	rc = c_conn->ops.pre_kickoff(connector, c_conn->display, &params);
 
+	display->queue_cmd_waits = false;
 end:
 	return rc;
 }