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Suraj Kandpal

2025-Jun-20 06:34 UTC

[PATCH 00/13] Modify drm helpers to use luminance

This series modifies drm dp edp helpers so that drivers can now use them
to manipulate brightness using luminance value via the
PANEL_TARGET_LUMINANCE_VALUE register. This feature was
introduced frin eDP 1.5.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>

Suraj Kandpal (13):
  drm/dp: Introduce new member in drm_backlight_info
  drm/dp: Add argument in drm_edp_backlight_init
  drm/dp: Add argument for max luminance in drm_edp_backlight_init
  drm/dp: Move from u16 to u32 for max in drm_edp_backlight_info
  drm/dp: Change current_level argument type to u32
  drm/dp: Modify drm_edp_probe_state
  drm/dp: Change argument type for drm_edp_backlight_set_level
  drm/dp: Modify drm_edp_backlight_set_level
  drm/dp: Change argument type of drm_edp_backlight_enable
  drm/dp: Enable backlight control using luminance
  drm/i915/backlight: Use drm helper to initialize edp backlight
  drm/i915/backlight: Use drm helper to set edp backlight
  drm/i915/backlight: Use drm_edp_backlight_enable

 drivers/gpu/drm/display/drm_dp_helper.c       |  92 ++++++++----
 .../drm/i915/display/intel_dp_aux_backlight.c | 140 ++++++------------
 drivers/gpu/drm/nouveau/dispnv50/disp.c       |   2 +-
 drivers/gpu/drm/nouveau/nouveau_backlight.c   |   7 +-
 include/drm/display/drm_dp_helper.h           |  10 +-
 5 files changed, 127 insertions(+), 124 deletions(-)

-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 01/13] drm/dp: Introduce new member in drm_backlight_info

Introduce luminance_set flag which indicates if we can manipulate
backlight using luminance value or not which is only possible
after eDP v1.5.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 8 ++++++--
 include/drm/display/drm_dp_helper.h     | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index 385a1bfdb272..e817bed9ffc6 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4277,11 +4277,15 @@ drm_edp_backlight_init(struct drm_dp_aux *aux, struct
drm_edp_backlight_info *bl
 		bl->aux_set = true;
 	if (edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
 		bl->lsb_reg_used = true;
+	if ((edp_dpcd[0] & DP_EDP_15) && edp_dpcd[3] &
+	    (DP_EDP_PANEL_LUMINANCE_CONTROL_CAPABLE))
+		bl->luminance_set = true;
 
 	/* Sanity check caps */
-	if (!bl->aux_set && !(edp_dpcd[2] &
DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) {
+	if (!bl->aux_set && !(edp_dpcd[2] &
DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP) &&
+	    !bl->luminance_set) {
 		drm_dbg_kms(aux->drm_dev,
-			    "%s: Panel supports neither AUX or PWM brightness control?
Aborting\n",
+			    "%s: Panel does not support AUX, PWM or luminance-based brightness
control. Aborting\n",
 			    aux->name);
 		return -EINVAL;
 	}
diff --git a/include/drm/display/drm_dp_helper.h
b/include/drm/display/drm_dp_helper.h
index 3e35a68b2b41..e3b13858c8a9 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -855,6 +855,7 @@ struct drm_edp_backlight_info {
 	bool lsb_reg_used : 1;
 	bool aux_enable : 1;
 	bool aux_set : 1;
+	bool luminance_set : 1;
 };
 
 int
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 02/13] drm/dp: Add argument in drm_edp_backlight_init

Add bool argument in drm_edp_backlight init to provide the drivers
option to choose if they want to use luminance values to
manipulate brightness.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c               | 7 ++++---
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 2 +-
 drivers/gpu/drm/nouveau/nouveau_backlight.c           | 2 +-
 include/drm/display/drm_dp_helper.h                   | 2 +-
 4 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index e817bed9ffc6..2a662951f7a8 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4255,6 +4255,7 @@ drm_edp_backlight_probe_state(struct drm_dp_aux *aux,
struct drm_edp_backlight_i
  * @edp_dpcd: A cached copy of the eDP DPCD
  * @current_level: Where to store the probed brightness level, if any
  * @current_mode: Where to store the currently set backlight control mode
+ * @need_luminance: Tells us if a we want to manipulate backlight using
luminance values
  *
  * Initializes a &drm_edp_backlight_info struct by probing @aux for
it's backlight capabilities,
  * along with also probing the current and maximum supported brightness levels.
@@ -4267,7 +4268,7 @@ drm_edp_backlight_probe_state(struct drm_dp_aux *aux,
struct drm_edp_backlight_i
 int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info
*bl,
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
-		       u16 *current_level, u8 *current_mode)
+		       u16 *current_level, u8 *current_mode, bool need_luminance)
 {
 	int ret;
 
@@ -4278,7 +4279,7 @@ drm_edp_backlight_init(struct drm_dp_aux *aux, struct
drm_edp_backlight_info *bl
 	if (edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
 		bl->lsb_reg_used = true;
 	if ((edp_dpcd[0] & DP_EDP_15) && edp_dpcd[3] &
-	    (DP_EDP_PANEL_LUMINANCE_CONTROL_CAPABLE))
+	    (DP_EDP_PANEL_LUMINANCE_CONTROL_CAPABLE) && need_luminance)
 		bl->luminance_set = true;
 
 	/* Sanity check caps */
@@ -4396,7 +4397,7 @@ int drm_panel_dp_aux_backlight(struct drm_panel *panel,
struct drm_dp_aux *aux)
 	bl->aux = aux;
 
 	ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,
-				     &current_level, &current_mode);
+				     &current_level, &current_mode, false);
 	if (ret < 0)
 		return ret;
 
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 271b27c9de51..dc6f6680774f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -600,7 +600,7 @@ static int intel_dp_aux_vesa_setup_backlight(struct
intel_connector *connector,
 	} else {
 		ret = drm_edp_backlight_init(&intel_dp->aux,
&panel->backlight.edp.vesa.info,
 					     panel->vbt.backlight.pwm_freq_hz, intel_dp->edp_dpcd,
-					     &current_level, &current_mode);
+					     &current_level, &current_mode, false);
 		if (ret < 0)
 			return ret;
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c
b/drivers/gpu/drm/nouveau/nouveau_backlight.c
index 9aae26eb7d8f..7d93266bf26a 100644
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
@@ -262,7 +262,7 @@ nv50_backlight_init(struct nouveau_backlight *bl,
 				 nv_conn->base.name);
 
 			ret = drm_edp_backlight_init(&nv_conn->aux, &bl->edp_info, 0,
edp_dpcd,
-						     &current_level, &current_mode);
+						     &current_level, &current_mode, false);
 			if (ret < 0)
 				return ret;
 
diff --git a/include/drm/display/drm_dp_helper.h
b/include/drm/display/drm_dp_helper.h
index e3b13858c8a9..fcbf447206cf 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -861,7 +861,7 @@ struct drm_edp_backlight_info {
 int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info
*bl,
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
-		       u16 *current_level, u8 *current_mode);
+		       u16 *current_level, u8 *current_mode, bool need_luminance);
 int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
 				u16 level);
 int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 03/13] drm/dp: Add argument for max luminance in drm_edp_backlight_init

Add new argument to drm_edp_backlight_init which gives the
max_luminance which will be needed to set the max values for
backlight.

--v2
-Use pass only max luminance instead of luminance_range_info struct
[Arun]

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c               | 4 +++-
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 6 ++++--
 drivers/gpu/drm/nouveau/nouveau_backlight.c           | 3 ++-
 include/drm/display/drm_dp_helper.h                   | 1 +
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index 2a662951f7a8..9df95776d1cb 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4251,6 +4251,7 @@ drm_edp_backlight_probe_state(struct drm_dp_aux *aux,
struct drm_edp_backlight_i
  * interface.
  * @aux: The DP aux device to use for probing
  * @bl: The &drm_edp_backlight_info struct to fill out with information on
the backlight
+ * @max_luminance: max luminance when need luminance is set as true
  * @driver_pwm_freq_hz: Optional PWM frequency from the driver in hz
  * @edp_dpcd: A cached copy of the eDP DPCD
  * @current_level: Where to store the probed brightness level, if any
@@ -4267,6 +4268,7 @@ drm_edp_backlight_probe_state(struct drm_dp_aux *aux,
struct drm_edp_backlight_i
  */
 int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info
*bl,
+		       u32 max_luminance,
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
 		       u16 *current_level, u8 *current_mode, bool need_luminance)
 {
@@ -4396,7 +4398,7 @@ int drm_panel_dp_aux_backlight(struct drm_panel *panel,
struct drm_dp_aux *aux)
 
 	bl->aux = aux;
 
-	ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,
+	ret = drm_edp_backlight_init(aux, &bl->info, 0, 0, edp_dpcd,
 				     &current_level, &current_mode, false);
 	if (ret < 0)
 		return ret;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index dc6f6680774f..ab594bf028da 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -599,8 +599,10 @@ static int intel_dp_aux_vesa_setup_backlight(struct
intel_connector *connector,
 			    connector->base.base.id, connector->base.name);
 	} else {
 		ret = drm_edp_backlight_init(&intel_dp->aux,
&panel->backlight.edp.vesa.info,
-					     panel->vbt.backlight.pwm_freq_hz, intel_dp->edp_dpcd,
-					     &current_level, &current_mode, false);
+					     luminance_range->max_luminance,
+					     panel->vbt.backlight.pwm_freq_hz,
+					     intel_dp->edp_dpcd, &current_level, &current_mode,
+					     false);
 		if (ret < 0)
 			return ret;
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c
b/drivers/gpu/drm/nouveau/nouveau_backlight.c
index 7d93266bf26a..d45619db02a2 100644
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
@@ -261,7 +261,8 @@ nv50_backlight_init(struct nouveau_backlight *bl,
 			NV_DEBUG(drm, "DPCD backlight controls supported on %s\n",
 				 nv_conn->base.name);
 
-			ret = drm_edp_backlight_init(&nv_conn->aux, &bl->edp_info, 0,
edp_dpcd,
+			ret = drm_edp_backlight_init(&nv_conn->aux, &bl->edp_info,
+						     0, 0, edp_dpcd,
 						     &current_level, &current_mode, false);
 			if (ret < 0)
 				return ret;
diff --git a/include/drm/display/drm_dp_helper.h
b/include/drm/display/drm_dp_helper.h
index fcbf447206cf..91094a38594c 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -860,6 +860,7 @@ struct drm_edp_backlight_info {
 
 int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info
*bl,
+		       u32 max_luminance,
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
 		       u16 *current_level, u8 *current_mode, bool need_luminance);
 int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 04/13] drm/dp: Move from u16 to u32 for max in drm_edp_backlight_info

Use u32 instead of u16 for max variable in drm_edp_backlight_info
since it can now hold max luminance range value which is u32.
We will set this max with max_luminance value when luminance_set is
true.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 10 +++++++---
 include/drm/display/drm_dp_helper.h     |  2 +-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index 9df95776d1cb..90b23f78a12d 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4293,9 +4293,13 @@ drm_edp_backlight_init(struct drm_dp_aux *aux, struct
drm_edp_backlight_info *bl
 		return -EINVAL;
 	}
 
-	ret = drm_edp_backlight_probe_max(aux, bl, driver_pwm_freq_hz, edp_dpcd);
-	if (ret < 0)
-		return ret;
+	if (bl->luminance_set) {
+		bl->max = max_luminance;
+	} else {
+		ret = drm_edp_backlight_probe_max(aux, bl, driver_pwm_freq_hz, edp_dpcd);
+		if (ret < 0)
+			return ret;
+	}
 
 	ret = drm_edp_backlight_probe_state(aux, bl, current_mode);
 	if (ret < 0)
diff --git a/include/drm/display/drm_dp_helper.h
b/include/drm/display/drm_dp_helper.h
index 91094a38594c..6176e0b5ea1a 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -850,7 +850,7 @@ drm_dp_has_quirk(const struct drm_dp_desc *desc, enum
drm_dp_quirk quirk)
 struct drm_edp_backlight_info {
 	u8 pwmgen_bit_count;
 	u8 pwm_freq_pre_divider;
-	u16 max;
+	u32 max;
 
 	bool lsb_reg_used : 1;
 	bool aux_enable : 1;
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 05/13] drm/dp: Change current_level argument type to u32

Change the current_level argument type to u32 from u16
since it can now carry the value which it gets from
DP_EDP_PANEL_TARGET_LUMINANCE_VALUE.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c               | 4 ++--
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 2 +-
 drivers/gpu/drm/nouveau/nouveau_backlight.c           | 2 +-
 include/drm/display/drm_dp_helper.h                   | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index 90b23f78a12d..daeb3bdc87a3 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4270,7 +4270,7 @@ int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info
*bl,
 		       u32 max_luminance,
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
-		       u16 *current_level, u8 *current_mode, bool need_luminance)
+		       u32 *current_level, u8 *current_mode, bool need_luminance)
 {
 	int ret;
 
@@ -4378,7 +4378,7 @@ int drm_panel_dp_aux_backlight(struct drm_panel *panel,
struct drm_dp_aux *aux)
 {
 	struct dp_aux_backlight *bl;
 	struct backlight_properties props = { 0 };
-	u16 current_level;
+	u32 current_level;
 	u8 current_mode;
 	u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
 	int ret;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index ab594bf028da..800d07c7f041 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -580,7 +580,7 @@ static int intel_dp_aux_vesa_setup_backlight(struct
intel_connector *connector,
 		&connector->base.display_info.luminance_range;
 	struct intel_dp *intel_dp = intel_attached_dp(connector);
 	struct intel_panel *panel = &connector->panel;
-	u16 current_level;
+	u32 current_level;
 	u8 current_mode;
 	int ret;
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c
b/drivers/gpu/drm/nouveau/nouveau_backlight.c
index d45619db02a2..4a75d146a171 100644
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
@@ -245,7 +245,7 @@ nv50_backlight_init(struct nouveau_backlight *bl,
 
 	if (nv_conn->type == DCB_CONNECTOR_eDP) {
 		int ret;
-		u16 current_level;
+		u32 current_level;
 		u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
 		u8 current_mode;
 
diff --git a/include/drm/display/drm_dp_helper.h
b/include/drm/display/drm_dp_helper.h
index 6176e0b5ea1a..21984bac0743 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -862,7 +862,7 @@ int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info
*bl,
 		       u32 max_luminance,
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
-		       u16 *current_level, u8 *current_mode, bool need_luminance);
+		       u32 *current_level, u8 *current_mode, bool need_luminance);
 int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
 				u16 level);
 int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 06/13] drm/dp: Modify drm_edp_probe_state

Modify drm_edp_probe_state to read current level from
DP_EDP_PANEL_TARGET_LUMINANCE_VALUE. We divide it by
1000 since the value in this register is in millinits.

--v2
-Add comment on the unit sent back [Arun]

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 40 ++++++++++++++++++-------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index daeb3bdc87a3..53f02dc6c3f1 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4209,7 +4209,7 @@ drm_edp_backlight_probe_state(struct drm_dp_aux *aux,
struct drm_edp_backlight_i
 			      u8 *current_mode)
 {
 	int ret;
-	u8 buf[2];
+	u8 buf[3];
 	u8 mode_reg;
 
 	ret = drm_dp_dpcd_read_byte(aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
&mode_reg);
@@ -4226,17 +4226,37 @@ drm_edp_backlight_probe_state(struct drm_dp_aux *aux,
struct drm_edp_backlight_i
 	if (*current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) {
 		int size = 1 + bl->lsb_reg_used;
 
-		ret = drm_dp_dpcd_read_data(aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, buf, size);
-		if (ret < 0) {
-			drm_dbg_kms(aux->drm_dev, "%s: Failed to read backlight level:
%d\n",
-				    aux->name, ret);
-			return ret;
+		if (bl->luminance_set) {
+			ret = drm_dp_dpcd_read_data(aux, DP_EDP_PANEL_TARGET_LUMINANCE_VALUE,
+						    buf, sizeof(buf));
+			if (ret < 0) {
+				drm_dbg_kms(aux->drm_dev,
+					    "%s: Failed to read backlight level: %d\n",
+					    aux->name, ret);
+				return ret;
 		}
 
-		if (bl->lsb_reg_used)
-			return (buf[0] << 8) | buf[1];
-		else
-			return buf[0];
+		/*
+		 * Incase luminance is set we want to send the value back in nits but since
+		 * DP_EDP_PANEL_TARGET_LUMINANCE stores values in millinits we need to divide
+		 * by 1000.
+		 */
+		return (buf[0] | buf[1] << 8 | buf[2] << 16) / 1000;
+		} else {
+			ret = drm_dp_dpcd_read_data(aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
+						    buf, size);
+			if (ret < 0) {
+				drm_dbg_kms(aux->drm_dev,
+					    "%s: Failed to read backlight level: %d\n",
+					    aux->name, ret);
+				return ret;
+			}
+
+			if (bl->lsb_reg_used)
+				return (buf[0] << 8) | buf[1];
+			else
+				return buf[0];
+		}
 	}
 
 	/*
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 07/13] drm/dp: Change argument type for drm_edp_backlight_set_level

Use u32 for level variable as one may need to pass value for
DP_EDP_PANEL_TARGET_LUMINANCE_VALUE.

--v2
-Typecase is not needed [Jani]

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 2 +-
 include/drm/display/drm_dp_helper.h     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index 53f02dc6c3f1..4d8829e00599 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -3957,7 +3957,7 @@ EXPORT_SYMBOL(drm_dp_pcon_convert_rgb_to_ycbcr);
  * Returns: %0 on success, negative error code on failure
  */
 int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
-				u16 level)
+				u32 level)
 {
 	int ret;
 	u8 buf[2] = { 0 };
diff --git a/include/drm/display/drm_dp_helper.h
b/include/drm/display/drm_dp_helper.h
index 21984bac0743..56e34568a16b 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -864,7 +864,7 @@ drm_edp_backlight_init(struct drm_dp_aux *aux, struct
drm_edp_backlight_info *bl
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
 		       u32 *current_level, u8 *current_mode, bool need_luminance);
 int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
-				u16 level);
+				u32 level);
 int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
 			     u16 level);
 int drm_edp_backlight_disable(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl);
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 08/13] drm/dp: Modify drm_edp_backlight_set_level

Modify drm_edp_backlight_set_level to be able to set the value
for register in DP_EDP_PANEL_TARGET_LUMINANCE_VALUE. We multiply
the level with 1000 since we get the value in Nits and the
register accepts it in milliNits.

--v2
-Add comment regarding the unit [Arun]

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index 4d8829e00599..c078e444014d 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -3960,20 +3960,28 @@ int drm_edp_backlight_set_level(struct drm_dp_aux *aux,
const struct drm_edp_bac
 				u32 level)
 {
 	int ret;
-	u8 buf[2] = { 0 };
+	unsigned int offset = DP_EDP_BACKLIGHT_BRIGHTNESS_MSB;
+	u8 buf[3] = { 0 };
 
 	/* The panel uses the PWM for controlling brightness levels */
-	if (!bl->aux_set)
+	if (!(bl->aux_set || bl->luminance_set))
 		return 0;
 
-	if (bl->lsb_reg_used) {
+	if (bl->luminance_set) {
+		level = level * 1000;
+		level &= 0xffffff;
+		buf[0] = (level & 0x0000ff);
+		buf[1] = (level & 0x00ff00) >> 8;
+		buf[2] = (level & 0xff0000) >> 16;
+		offset = DP_EDP_PANEL_TARGET_LUMINANCE_VALUE;
+	} else if (bl->lsb_reg_used) {
 		buf[0] = (level & 0xff00) >> 8;
 		buf[1] = (level & 0x00ff);
 	} else {
 		buf[0] = level;
 	}
 
-	ret = drm_dp_dpcd_write_data(aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, buf,
sizeof(buf));
+	ret = drm_dp_dpcd_write_data(aux, offset, buf, sizeof(buf));
 	if (ret < 0) {
 		drm_err(aux->drm_dev,
 			"%s: Failed to write aux backlight level: %d\n",
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 09/13] drm/dp: Change argument type of drm_edp_backlight_enable

Change the argument type to u32 for the default level being sent
since it has to now account for luminance value which has to be
set for DP_EDP_PANEL_LUMINANCE_TARGET_VALUE.

--v2
-No need to typecast [Jani]

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 2 +-
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 2 +-
 include/drm/display/drm_dp_helper.h     | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index c078e444014d..fc1eb8b7bbc1 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4044,7 +4044,7 @@ drm_edp_backlight_set_enable(struct drm_dp_aux *aux, const
struct drm_edp_backli
  * Returns: %0 on success, negative error code on failure.
  */
 int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
-			     const u16 level)
+			     const u32 level)
 {
 	int ret;
 	u8 dpcd_buf;
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index e5d37eee4301..e97e39abf3a2 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1839,7 +1839,7 @@ nv50_sor_atomic_enable(struct drm_encoder *encoder, struct
drm_atomic_state *sta
 		backlight = nv_connector->backlight;
 		if (backlight && backlight->uses_dpcd)
 			drm_edp_backlight_enable(&nv_connector->aux,
&backlight->edp_info,
-						 (u16)backlight->dev->props.brightness);
+						 backlight->dev->props.brightness);
 #endif
 
 		break;
diff --git a/include/drm/display/drm_dp_helper.h
b/include/drm/display/drm_dp_helper.h
index 56e34568a16b..774c6d3e2001 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -866,7 +866,7 @@ drm_edp_backlight_init(struct drm_dp_aux *aux, struct
drm_edp_backlight_info *bl
 int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
 				u32 level);
 int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl,
-			     u16 level);
+			     u32 level);
 int drm_edp_backlight_disable(struct drm_dp_aux *aux, const struct
drm_edp_backlight_info *bl);
 
 #if IS_ENABLED(CONFIG_DRM_KMS_HELPER) &&
(IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 10/13] drm/dp: Enable backlight control using luminance

Add flag to enable brightness control via luminance value
when enabling edp backlight.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index fc1eb8b7bbc1..db7896c7edb8 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4054,6 +4054,9 @@ int drm_edp_backlight_enable(struct drm_dp_aux *aux, const
struct drm_edp_backli
 	else
 		dpcd_buf = DP_EDP_BACKLIGHT_CONTROL_MODE_PWM;
 
+	if (bl->luminance_set)
+		dpcd_buf |= DP_EDP_PANEL_LUMINANCE_CONTROL_ENABLE;
+
 	if (bl->pwmgen_bit_count) {
 		ret = drm_dp_dpcd_write_byte(aux, DP_EDP_PWMGEN_BIT_COUNT,
bl->pwmgen_bit_count);
 		if (ret < 0)
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 11/13] drm/i915/backlight: Use drm helper to initialize edp backlight

Now that drm_edp_backlight init has been modified to take
into account the setup of lumininace based brightness manipulation
we can just use that.

--v2
-Fix commit message [Arun]

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
---
 .../drm/i915/display/intel_dp_aux_backlight.c | 98 +++++++++----------
 1 file changed, 48 insertions(+), 50 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 800d07c7f041..117c762fa2fe 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -584,9 +584,37 @@ static int intel_dp_aux_vesa_setup_backlight(struct
intel_connector *connector,
 	u8 current_mode;
 	int ret;
 
-	if (panel->backlight.edp.vesa.luminance_control_support) {
+	ret = drm_edp_backlight_init(&intel_dp->aux,
&panel->backlight.edp.vesa.info,
+				     luminance_range->max_luminance,
+				     panel->vbt.backlight.pwm_freq_hz,
+				     intel_dp->edp_dpcd, &current_level, &current_mode,
+				     false);
+	if (ret < 0)
+		return ret;
+
+	drm_dbg_kms(display->drm,
+		    "[CONNECTOR:%d:%s] AUX VESA backlight enable is controlled through
%s\n",
+		    connector->base.base.id, connector->base.name,
+		    dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_enable));
+	drm_dbg_kms(display->drm,
+		    "[CONNECTOR:%d:%s] AUX VESA backlight level is controlled through
%s\n",
+		    connector->base.base.id, connector->base.name,
+		    dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_set));
+
+	if (!panel->backlight.edp.vesa.info.aux_set ||
+	    !panel->backlight.edp.vesa.info.aux_enable) {
+		ret = panel->backlight.pwm_funcs->setup(connector, pipe);
+		if (ret < 0) {
+			drm_err(display->drm,
+				"[CONNECTOR:%d:%s] Failed to setup PWM backlight controls for eDP
backlight: %d\n",
+				connector->base.base.id, connector->base.name, ret);
+			return ret;
+		}
+	}
+
+	if (panel->backlight.edp.vesa.info.luminance_set) {
 		if (luminance_range->max_luminance) {
-			panel->backlight.max = luminance_range->max_luminance;
+			panel->backlight.max = panel->backlight.edp.vesa.info.max;
 			panel->backlight.min = luminance_range->min_luminance;
 		} else {
 			panel->backlight.max = 512;
@@ -597,56 +625,26 @@ static int intel_dp_aux_vesa_setup_backlight(struct
intel_connector *connector,
 		drm_dbg_kms(display->drm,
 			    "[CONNECTOR:%d:%s] AUX VESA Nits backlight level is controlled
through DPCD\n",
 			    connector->base.base.id, connector->base.name);
-	} else {
-		ret = drm_edp_backlight_init(&intel_dp->aux,
&panel->backlight.edp.vesa.info,
-					     luminance_range->max_luminance,
-					     panel->vbt.backlight.pwm_freq_hz,
-					     intel_dp->edp_dpcd, &current_level, &current_mode,
-					     false);
-		if (ret < 0)
-			return ret;
-
-		drm_dbg_kms(display->drm,
-			    "[CONNECTOR:%d:%s] AUX VESA backlight enable is controlled through
%s\n",
-			    connector->base.base.id, connector->base.name,
-			    dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_enable));
-		drm_dbg_kms(display->drm,
-			    "[CONNECTOR:%d:%s] AUX VESA backlight level is controlled through
%s\n",
-			    connector->base.base.id, connector->base.name,
-			    dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_set));
-
-		if (!panel->backlight.edp.vesa.info.aux_set ||
-		    !panel->backlight.edp.vesa.info.aux_enable) {
-			ret = panel->backlight.pwm_funcs->setup(connector, pipe);
-			if (ret < 0) {
-				drm_err(display->drm,
-					"[CONNECTOR:%d:%s] Failed to setup PWM backlight controls for eDP
backlight: %d\n",
-					connector->base.base.id, connector->base.name, ret);
-				return ret;
-			}
+	} else if (panel->backlight.edp.vesa.info.aux_set) {
+		panel->backlight.max = panel->backlight.edp.vesa.info.max;
+		panel->backlight.min = 0;
+		if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) {
+			panel->backlight.level = current_level;
+			panel->backlight.enabled = panel->backlight.level != 0;
+		} else {
+			panel->backlight.level = panel->backlight.max;
+			panel->backlight.enabled = false;
 		}
-
-		if (panel->backlight.edp.vesa.info.aux_set) {
-			panel->backlight.max = panel->backlight.edp.vesa.info.max;
-			panel->backlight.min = 0;
-			if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) {
-				panel->backlight.level = current_level;
-				panel->backlight.enabled = panel->backlight.level != 0;
-			} else {
-				panel->backlight.level = panel->backlight.max;
-				panel->backlight.enabled = false;
-			}
+	} else {
+		panel->backlight.max = panel->backlight.pwm_level_max;
+		panel->backlight.min = panel->backlight.pwm_level_min;
+		if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_PWM) {
+			panel->backlight.level +			
panel->backlight.pwm_funcs->get(connector, pipe);
+			panel->backlight.enabled = panel->backlight.pwm_enabled;
 		} else {
-			panel->backlight.max = panel->backlight.pwm_level_max;
-			panel->backlight.min = panel->backlight.pwm_level_min;
-			if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_PWM) {
-				panel->backlight.level -				
panel->backlight.pwm_funcs->get(connector, pipe);
-				panel->backlight.enabled = panel->backlight.pwm_enabled;
-			} else {
-				panel->backlight.level = panel->backlight.max;
-				panel->backlight.enabled = false;
-			}
+			panel->backlight.level = panel->backlight.max;
+			panel->backlight.enabled = false;
 		}
 	}
 
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 12/13] drm/i915/backlight: Use drm helper to set edp backlight

Now that the drm helper sets the backlight using luminance
too we can use that. Remove the obselete function.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 .../drm/i915/display/intel_dp_aux_backlight.c | 34 ++-----------------
 1 file changed, 3 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 117c762fa2fe..8f33c5b78079 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -475,31 +475,6 @@ static u32 intel_dp_aux_vesa_get_backlight(struct
intel_connector *connector, en
 	return connector->panel.backlight.level;
 }
 
-static int
-intel_dp_aux_vesa_set_luminance(struct intel_connector *connector, u32 level)
-{
-	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
-	u8 buf[3];
-	int ret;
-
-	level = level * 1000;
-	level &= 0xffffff;
-	buf[0] = (level & 0x0000ff);
-	buf[1] = (level & 0x00ff00) >> 8;
-	buf[2] = (level & 0xff0000) >> 16;
-
-	ret = drm_dp_dpcd_write(&intel_dp->aux,
DP_EDP_PANEL_TARGET_LUMINANCE_VALUE,
-				buf, sizeof(buf));
-	if (ret != sizeof(buf)) {
-		drm_err(intel_dp->aux.drm_dev,
-			"%s: Failed to set VESA Aux Luminance: %d\n",
-			intel_dp->aux.name, ret);
-		return -EINVAL;
-	} else {
-		return 0;
-	}
-}
-
 static void
 intel_dp_aux_vesa_set_backlight(const struct drm_connector_state *conn_state,
u32 level)
 {
@@ -507,11 +482,6 @@ intel_dp_aux_vesa_set_backlight(const struct
drm_connector_state *conn_state, u3
 	struct intel_panel *panel = &connector->panel;
 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
 
-	if (panel->backlight.edp.vesa.luminance_control_support) {
-		if (!intel_dp_aux_vesa_set_luminance(connector, level))
-			return;
-	}
-
 	if (!panel->backlight.edp.vesa.info.aux_set) {
 		const u32 pwm_level = intel_backlight_level_to_pwm(connector, level);
 
@@ -537,7 +507,9 @@ intel_dp_aux_vesa_enable_backlight(const struct
intel_crtc_state *crtc_state,
 		if (ret == 1)
 			return;
 
-		if (!intel_dp_aux_vesa_set_luminance(connector, level))
+		if (!drm_edp_backlight_set_level(&intel_dp->aux,
+						 &panel->backlight.edp.vesa.info,
+						 level))
 			return;
 	}
 
-- 
2.34.1

Suraj Kandpal

2025-Jun-20 06:34 UTC

head link

[PATCH v3 13/13] drm/i915/backlight: Use drm_edp_backlight_enable

Use drm dp helper to enable backlight now that it has been modified
to set PANEL_LUMINANCE_CONTROL_ENABLE bit based on if capability
supports it and the driver wants it. Remove the dead code.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>
---
 .../gpu/drm/i915/display/intel_dp_aux_backlight.c  | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 8f33c5b78079..25332a7b7707 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -498,20 +498,6 @@ intel_dp_aux_vesa_enable_backlight(const struct
intel_crtc_state *crtc_state,
 	struct intel_connector *connector =
to_intel_connector(conn_state->connector);
 	struct intel_panel *panel = &connector->panel;
 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
-	int ret;
-
-	if (panel->backlight.edp.vesa.luminance_control_support) {
-		ret = drm_dp_dpcd_writeb(&intel_dp->aux,
DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
-					 DP_EDP_PANEL_LUMINANCE_CONTROL_ENABLE);
-
-		if (ret == 1)
-			return;
-
-		if (!drm_edp_backlight_set_level(&intel_dp->aux,
-						 &panel->backlight.edp.vesa.info,
-						 level))
-			return;
-	}
 
 	if (!panel->backlight.edp.vesa.info.aux_enable) {
 		u32 pwm_level;
-- 
2.34.1

Jani Nikula

2025-Jun-25 09:03 UTC

head link

[PATCH 00/13] Modify drm helpers to use luminance

On Fri, 20 Jun 2025, Suraj Kandpal <suraj.kandpal at intel.com>
wrote:> This series modifies drm dp edp helpers so that drivers can now use them
> to manipulate brightness using luminance value via the
> PANEL_TARGET_LUMINANCE_VALUE register. This feature was
> introduced frin eDP 1.5.
>
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
>
> Suraj Kandpal (13):
>   drm/dp: Introduce new member in drm_backlight_info
>   drm/dp: Add argument in drm_edp_backlight_init
>   drm/dp: Add argument for max luminance in drm_edp_backlight_init
>   drm/dp: Move from u16 to u32 for max in drm_edp_backlight_info
>   drm/dp: Change current_level argument type to u32
>   drm/dp: Modify drm_edp_probe_state
>   drm/dp: Change argument type for drm_edp_backlight_set_level
>   drm/dp: Modify drm_edp_backlight_set_level
>   drm/dp: Change argument type of drm_edp_backlight_enable
>   drm/dp: Enable backlight control using luminance
>   drm/i915/backlight: Use drm helper to initialize edp backlight
>   drm/i915/backlight: Use drm helper to set edp backlight
>   drm/i915/backlight: Use drm_edp_backlight_enable
Acked-by: Jani Nikula <jani.nikula at intel.com>

for merging the last three patches via drm-misc.

However, would be great to solicit feedback on the series from non-Intel
folks too. Cc: Lyude who's worked on DPCD brightness before.

BR,
Jani.
>
>  drivers/gpu/drm/display/drm_dp_helper.c       |  92 ++++++++----
>  .../drm/i915/display/intel_dp_aux_backlight.c | 140 ++++++------------
>  drivers/gpu/drm/nouveau/dispnv50/disp.c       |   2 +-
>  drivers/gpu/drm/nouveau/nouveau_backlight.c   |   7 +-
>  include/drm/display/drm_dp_helper.h           |  10 +-
>  5 files changed, 127 insertions(+), 124 deletions(-)
-- 
Jani Nikula, Intel

Nouveau - Jun 2025 - [PATCH v3 03/13] drm/dp: Add argument for max luminance in drm_edp_backlight_init

[PATCH 00/13] Modify drm helpers to use luminance

[PATCH v3 01/13] drm/dp: Introduce new member in drm_backlight_info

[PATCH v3 02/13] drm/dp: Add argument in drm_edp_backlight_init

[PATCH v3 03/13] drm/dp: Add argument for max luminance in drm_edp_backlight_init

[PATCH v3 04/13] drm/dp: Move from u16 to u32 for max in drm_edp_backlight_info

[PATCH v3 05/13] drm/dp: Change current_level argument type to u32

[PATCH v3 06/13] drm/dp: Modify drm_edp_probe_state

[PATCH v3 07/13] drm/dp: Change argument type for drm_edp_backlight_set_level

[PATCH v3 08/13] drm/dp: Modify drm_edp_backlight_set_level

[PATCH v3 09/13] drm/dp: Change argument type of drm_edp_backlight_enable

[PATCH v3 10/13] drm/dp: Enable backlight control using luminance

[PATCH v3 11/13] drm/i915/backlight: Use drm helper to initialize edp backlight

[PATCH v3 12/13] drm/i915/backlight: Use drm helper to set edp backlight

[PATCH v3 13/13] drm/i915/backlight: Use drm_edp_backlight_enable

[PATCH 00/13] Modify drm helpers to use luminance