[Intel-gfx] [PATCH 4/4] drm/i915: switch off backlight for backlight class 0 brightness

[Jani Nikula]

Make backlight class sysfs brightness 0 value switch off the backlight
for connectors that have the backlight_power callback defined. For eDP,
this has the similar caveats regarding power savings as bl_power as only
the power sequencer backlight control is switched off.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/intel_panel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index c365f2a57c75..574690afadb3 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -986,7 +986,8 @@ static int intel_backlight_device_update_status(struct backlight_device *bd)
 	 */
 	if (panel->backlight.enabled) {
 		if (panel->backlight_power) {
-			bool enable = bd->props.power == FB_BLANK_UNBLANK;
+			bool enable = bd->props.power == FB_BLANK_UNBLANK &&
+				bd->props.brightness != 0;
 			panel->backlight_power(connector, enable);
 		}
 	} else {
-- 
1.9.1