This patch enables dynamic backlight by default for eDP
panel that supports this feature via DPCD register and
set minimum / maximum brightness to 0% and 100% of the
normal brightness.
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Signed-off-by: Puthikorn Voravootivat <puthik@xxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 31 +++++++++++++++++++++++----
1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
index f06c8381c74e..ae1b6fe67feb 100644
--- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
@@ -97,10 +97,24 @@ intel_dp_aux_set_backlight(struct intel_connector *connector, u32 level)
}
}
+/*
+ * Set minimum / maximum dynamic brightness percentage. This value is expressed
+ * as the percentage of normal brightness in 5% increments.
+ */
+static void
+intel_dp_aux_set_dynamic_backlight_percent(struct intel_dp *intel_dp,
+ u32 min, u32 max)
+{
+ u8 dbc[] = { DIV_ROUND_CLOSEST(min, 5), DIV_ROUND_CLOSEST(max, 5) };
+ drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET,
+ dbc, sizeof(dbc));
+}
+
static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
{
struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
uint8_t dpcd_buf = 0;
+ uint8_t new_dpcd_buf = 0;
uint8_t edp_backlight_mode = 0;
set_aux_backlight_enable(intel_dp, true);
@@ -110,16 +124,15 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
return;
}
+ new_dpcd_buf = dpcd_buf;
edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
switch (edp_backlight_mode) {
case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
- dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
- dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
- drm_dp_dpcd_writeb(&intel_dp->aux,
- DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf);
+ new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
+ new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
break;
/* Do nothing when it is already DPCD mode */
@@ -127,6 +140,16 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
default:
break;
}
+
+ if (intel_dp->edp_dpcd[2] & DP_EDP_DYNAMIC_BACKLIGHT_CAP) {
+ new_dpcd_buf |= DP_EDP_DYNAMIC_BACKLIGHT_ENABLE;
+ intel_dp_aux_set_dynamic_backlight_percent(intel_dp, 0, 100);
+ }
+
+ if (new_dpcd_buf != dpcd_buf) {
+ drm_dp_dpcd_writeb(&intel_dp->aux,
+ DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf);
+ }
}
static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
--
2.12.1.500.gab5fba24ee-goog
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