This patch adds option to enable dynamic backlight for eDP
panel that supports this feature via DPCD register and
set minimum / maximum brightness to 0% and 100% of the
normal brightness.
Signed-off-by: Puthikorn Voravootivat <puthik@xxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_params.c | 5 ++++
drivers/gpu/drm/i915/i915_params.h | 3 +-
drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 42 ++++++++++++++++++++++-----
3 files changed, 41 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 13cf3f1572ab..6eaf660e74da 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -65,6 +65,7 @@ struct i915_params i915 __read_mostly = {
.inject_load_failure = 0,
.enable_dpcd_backlight = -1,
.enable_gvt = false,
+ .enable_dbc = false,
};
module_param_named(modeset, i915.modeset, int, 0400);
@@ -255,3 +256,7 @@ MODULE_PARM_DESC(enable_dpcd_backlight,
module_param_named(enable_gvt, i915.enable_gvt, bool, 0400);
MODULE_PARM_DESC(enable_gvt,
"Enable support for Intel GVT-g graphics virtualization host support(default:false)");
+
+module_param_named(enable_dbc, i915.enable_dbc, bool, 0600);
+MODULE_PARM_DESC(enable_dbc,
+ "Enable support for dynamic backlight control (default:false)");
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index ac02efce6e22..2de3e2850b54 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -67,7 +67,8 @@
func(bool, nuclear_pageflip); \
func(bool, enable_dp_mst); \
func(int, enable_dpcd_backlight); \
- func(bool, enable_gvt)
+ func(bool, enable_gvt); \
+ func(bool, enable_dbc)
#define MEMBER(T, member) T member
struct i915_params {
diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
index 16ba1924308d..f1b7855a2d2a 100644
--- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
@@ -100,11 +100,26 @@ 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) };
+
+ if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET,
+ dbc, sizeof(dbc)) < 0) {
+ DRM_DEBUG_KMS("Failed to write aux DBC brightness level\n");
+ }
+}
+
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 edp_backlight_mode = 0;
+ uint8_t dpcd_buf, new_dpcd_buf, edp_backlight_mode;
if (drm_dp_dpcd_readb(&intel_dp->aux,
DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) != 1) {
@@ -113,18 +128,15 @@ 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;
- if (drm_dp_dpcd_writeb(&intel_dp->aux,
- DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf) < 0) {
- DRM_DEBUG_KMS("Failed to write aux backlight mode\n");
- }
+ 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 */
@@ -133,6 +145,20 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
break;
}
+ if (i915.enable_dbc &&
+ (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);
+ DRM_DEBUG_KMS("Enable dynamic brightness.\n");
+ }
+
+ if (new_dpcd_buf != dpcd_buf) {
+ if (drm_dp_dpcd_writeb(&intel_dp->aux,
+ DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf) < 0) {
+ DRM_DEBUG_KMS("Failed to write aux backlight mode\n");
+ }
+ }
+
set_aux_backlight_enable(intel_dp, true);
intel_dp_aux_set_backlight(connector, connector->panel.backlight.level);
}
--
2.13.0.219.gdb65acc882-goog
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