[Intel-gfx] [PATCH] drm/i915: Refine eDP aux backlight enable sequence.

[Lee, Shawn C]

Modify aux backlight enable sequence just like what we
did for genernal eDP panel.
1. Setup PWM freq and brightness level before enable display backlight.
2. Add T8 (valid data to backlight enable) delay.

Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Jose Roberto de Souza <jose.souza at intel.com>
Cc: Cooper Chiou <cooper.chiou at intel.com>

Signed-off-by: Lee, Shawn C <shawn.c.lee at intel.com>
---
 drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
index 7ded95a334db..c112e0b930de 100644
--- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
@@ -216,8 +216,12 @@ static void intel_dp_aux_enable_backlight(const struct intel_crtc_state *crtc_st
 		}
 	}
 
-	set_aux_backlight_enable(intel_dp, true);
 	intel_dp_aux_set_backlight(conn_state, connector->panel.backlight.level);
+
+	wait_remaining_ms_from_jiffies(intel_dp->last_power_on,
+				       intel_dp->backlight_on_delay);
+
+	set_aux_backlight_enable(intel_dp, true);
 }
 
 static void intel_dp_aux_disable_backlight(const struct drm_connector_state *old_conn_state)
-- 
2.7.4