On 08/12/2014 07:11 AM, Jani Nikula wrote:
This lets the userspace switch off the backlight using the backlight
class sysfs bl_power file. The switch is done using the power sequencer;
the backlight PWM, and everything else, remains enabled. The display
backlight won't draw power, but for maximum power savings the encoder
needs to be switched off.
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d8baf60ff3fd..f6e3e9a906b0 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1453,6 +1453,27 @@ void intel_edp_backlight_off(struct intel_dp *intel_dp)
intel_panel_disable_backlight(intel_dp->attached_connector);
}
+/*
+ * Hook for controlling the panel power control backlight through the bl_power
+ * sysfs attribute. Take care to handle multiple calls.
+ */
+static void intel_edp_backlight_power(struct intel_connector *connector,
+ bool enable)
+{
+ struct intel_dp *intel_dp = intel_attached_dp(&connector->base);
+ bool is_enabled = ironlake_get_pp_control(intel_dp) & EDP_BLC_ENABLE;
+
+ if (is_enabled == enable)
+ return;
+
+ DRM_DEBUG_KMS("\n");
+
+ if (enable)
+ _intel_edp_backlight_on(intel_dp);
+ else
+ _intel_edp_backlight_off(intel_dp);
Is there a good reason why we leave the PWM enabled? There is a small
power requirement to leave the PWM enabled.
+}
+
static void ironlake_edp_pll_on(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -4579,6 +4600,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
}
intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
+ intel_connector->panel.backlight_power = intel_edp_backlight_power;
intel_panel_setup_backlight(connector);
return true;
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