drm/i915: switch off backlight for backlight class 0 brightness

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@intel.com>
Reviewed_by: Clinton Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index af54356349291ab5f4f7a15a6a468bbe85c529ba..764f9283e572d9444a4ca2e18b0af485f90cdcd0 100644 (file)
--- 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 {