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

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

[Suraj Kandpal]

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@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 luminance range info 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 | 143 ++++++------------
 drivers/gpu/drm/nouveau/dispnv50/disp.c       |   2 +-
 drivers/gpu/drm/nouveau/nouveau_backlight.c   |   9 +-
 include/drm/display/drm_dp_helper.h           |  10 +-
 5 files changed, 128 insertions(+), 128 deletions(-)

-- 
2.34.1

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

[Suraj Kandpal]

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@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 57828f2b7b5a..41de7a92d76d 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4253,11 +4253,15 @@ 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 d9614e2c8939..b8fdc09737fc 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -844,6 +844,7 @@ 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

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

[Suraj Kandpal]

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@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 41de7a92d76d..99b27e5e3365 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4231,6 +4231,7 @@ 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.
@@ -4243,7 +4244,7 @@ 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;
 
@@ -4254,7 +4255,7 @@ 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 */
@@ -4372,7 +4373,7 @@ 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 8173de8aec63..6dab8a0c0d74 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -601,7 +601,7 @@ 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 d47442125fa1..b938684a9422 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 b8fdc09737fc..ef0786a0af4a 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -850,7 +850,7 @@ 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

[PATCH 03/13] drm/dp: Add argument for luminance range info in drm_edp_backlight_init

[Suraj Kandpal]

Add new argument to drm_edp_backlight_init which gives the
drm_luminance_range_info struct which will be needed to set the min
and max values for backlight.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c               | 5 ++++-
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 5 +++--
 drivers/gpu/drm/nouveau/nouveau_backlight.c           | 5 ++++-
 include/drm/display/drm_dp_helper.h                   | 1 +
 4 files 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 99b27e5e3365..3b309ac5190b 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4227,6 +4227,8 @@ 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
+ * @lr: The &drm_luminance_range_info struct which is used to get the min max when using
+ *luminance override
  * @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
@@ -4243,6 +4245,7 @@ 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,
+		       struct drm_luminance_range_info *lr,
 		       u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE],
 		       u16 *current_level, u8 *current_mode, bool need_luminance)
 {
@@ -4372,7 +4375,7 @@ 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, NULL, 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 6dab8a0c0d74..22af5cf83b1e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -600,8 +600,9 @@ 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, 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 b938684a9422..a3681e101d56 100644
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
@@ -234,6 +234,8 @@ nv50_backlight_init(struct nouveau_backlight *bl,
 		    const struct backlight_ops **ops)
 {
 	struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
+	struct drm_luminance_range_info *luminance_range =
+		&nv_conn->base.display_info.luminance_range;
 
 	/*
 	 * Note when this runs the connectors have not been probed yet,
@@ -261,7 +263,8 @@ 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,
+						     luminance_range, 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 ef0786a0af4a..6f53921f5dce 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -849,6 +849,7 @@ struct drm_edp_backlight_info {
 
 int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl,
+		       struct drm_luminance_range_info *lr,
 		       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

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

[Suraj Kandpal]

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@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 3b309ac5190b..1322bdfb6c8b 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4270,9 +4270,13 @@ 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 = lr->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 6f53921f5dce..39d644495f3e 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -839,7 +839,7 @@ 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

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

[Suraj Kandpal]

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@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 1322bdfb6c8b..c58973d8c5f0 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4247,7 +4247,7 @@ int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl,
 		       struct drm_luminance_range_info *lr,
 		       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;
 
@@ -4355,7 +4355,7 @@ 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 22af5cf83b1e..72cdb6b499c0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -581,7 +581,7 @@ 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 a3681e101d56..a430ee30060e 100644
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
@@ -247,7 +247,7 @@ 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 39d644495f3e..62be80417ded 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -851,7 +851,7 @@ int
 drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl,
 		       struct drm_luminance_range_info *lr,
 		       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

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

[Suraj Kandpal]

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.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 35 ++++++++++++++++++-------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index c58973d8c5f0..bb1242a1bf6b 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4185,7 +4185,7 @@ 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);
@@ -4202,17 +4202,32 @@ 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];
+		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

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

[Suraj Kandpal]

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

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 6 +++---
 include/drm/display/drm_dp_helper.h     | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index bb1242a1bf6b..895ed4a22fc3 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -3933,7 +3933,7 @@ 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 };
@@ -4047,7 +4047,7 @@ int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct drm_edp_backli
 		return ret < 0 ? ret : -EIO;
 	}
 
-	ret = drm_edp_backlight_set_level(aux, bl, level);
+	ret = drm_edp_backlight_set_level(aux, bl, (u32)level);
 	if (ret < 0)
 		return ret;
 	ret = drm_edp_backlight_set_enable(aux, bl, true);
@@ -4327,7 +4327,7 @@ static int dp_aux_backlight_update_status(struct backlight_device *bd)
 			bl->enabled = true;
 			return 0;
 		}
-		ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
+		ret = drm_edp_backlight_set_level(bl->aux, &bl->info, (u32)brightness);
 	} else {
 		if (bl->enabled) {
 			drm_edp_backlight_disable(bl->aux, &bl->info);
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
index 62be80417ded..6bce0176efd3 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -853,7 +853,7 @@ 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

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

[Jani Nikula]

On Fri, 11 Apr 2025, Suraj Kandpal <suraj.kandpal@intel.com> wrote:
> Use u32 for level variable as one may need to pass value for
> DP_EDP_PANEL_TARGET_LUMINANCE_VALUE.
>
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>  drivers/gpu/drm/display/drm_dp_helper.c | 6 +++---
>  include/drm/display/drm_dp_helper.h     | 2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> index bb1242a1bf6b..895ed4a22fc3 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -3933,7 +3933,7 @@ 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 };
> @@ -4047,7 +4047,7 @@ int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct drm_edp_backli
>  		return ret < 0 ? ret : -EIO;
>  	}
>  
> -	ret = drm_edp_backlight_set_level(aux, bl, level);
> +	ret = drm_edp_backlight_set_level(aux, bl, (u32)level);

What difference do you think the cast makes?

>  	if (ret < 0)
>  		return ret;
>  	ret = drm_edp_backlight_set_enable(aux, bl, true);
> @@ -4327,7 +4327,7 @@ static int dp_aux_backlight_update_status(struct backlight_device *bd)
>  			bl->enabled = true;
>  			return 0;
>  		}
> -		ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
> +		ret = drm_edp_backlight_set_level(bl->aux, &bl->info, (u32)brightness);

Ditto.

>  	} else {
>  		if (bl->enabled) {
>  			drm_edp_backlight_disable(bl->aux, &bl->info);
> diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
> index 62be80417ded..6bce0176efd3 100644
> --- a/include/drm/display/drm_dp_helper.h
> +++ b/include/drm/display/drm_dp_helper.h
> @@ -853,7 +853,7 @@ 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);

-- 
Jani Nikula, Intel

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

[Kandpal, Suraj]

> -----Original Message-----
> From: Jani Nikula <jani.nikula@linux.intel.com>
> Sent: Friday, April 11, 2025 4:09 PM
> To: Kandpal, Suraj <suraj.kandpal@intel.com>; nouveau@lists.freedesktop.org;
> dri-devel@lists.freedesktop.org; intel-xe@lists.freedesktop.org; intel-
> gfx@lists.freedesktop.org
> Cc: Nautiyal, Ankit K <ankit.k.nautiyal@intel.com>; Murthy, Arun R
> <arun.r.murthy@intel.com>; Kandpal, Suraj <suraj.kandpal@intel.com>
> Subject: Re: [PATCH 07/13] drm/dp: Change argument type for
> drm_edp_backlight_set_level
> 
> On Fri, 11 Apr 2025, Suraj Kandpal <suraj.kandpal@intel.com> wrote:
> > Use u32 for level variable as one may need to pass value for
> > DP_EDP_PANEL_TARGET_LUMINANCE_VALUE.
> >
> > Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> > ---
> >  drivers/gpu/drm/display/drm_dp_helper.c | 6 +++---
> >  include/drm/display/drm_dp_helper.h     | 2 +-
> >  2 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
> > b/drivers/gpu/drm/display/drm_dp_helper.c
> > index bb1242a1bf6b..895ed4a22fc3 100644
> > --- a/drivers/gpu/drm/display/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> > @@ -3933,7 +3933,7 @@
> 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 };
> > @@ -4047,7 +4047,7 @@ int drm_edp_backlight_enable(struct drm_dp_aux
> *aux, const struct drm_edp_backli
> >  		return ret < 0 ? ret : -EIO;
> >  	}
> >
> > -	ret = drm_edp_backlight_set_level(aux, bl, level);
> > +	ret = drm_edp_backlight_set_level(aux, bl, (u32)level);
> 
> What difference do you think the cast makes?

You are right this is not needed the var should be automatically be promoted will fix this here
And in another patch where I have done the same mistake.

Regards,
Suraj Kandpal

> 
> >  	if (ret < 0)
> >  		return ret;
> >  	ret = drm_edp_backlight_set_enable(aux, bl, true); @@ -4327,7
> > +4327,7 @@ static int dp_aux_backlight_update_status(struct
> backlight_device *bd)
> >  			bl->enabled = true;
> >  			return 0;
> >  		}
> > -		ret = drm_edp_backlight_set_level(bl->aux, &bl->info,
> brightness);
> > +		ret = drm_edp_backlight_set_level(bl->aux, &bl->info,
> > +(u32)brightness);
> 
> Ditto.
> 
> >  	} else {
> >  		if (bl->enabled) {
> >  			drm_edp_backlight_disable(bl->aux, &bl->info); diff --
> git
> > a/include/drm/display/drm_dp_helper.h
> > b/include/drm/display/drm_dp_helper.h
> > index 62be80417ded..6bce0176efd3 100644
> > --- a/include/drm/display/drm_dp_helper.h
> > +++ b/include/drm/display/drm_dp_helper.h
> > @@ -853,7 +853,7 @@ 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);
> 
> --
> Jani Nikula, Intel

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

[Suraj Kandpal]

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.

Signed-off-by: Suraj Kandpal <suraj.kandpal@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 895ed4a22fc3..bbe3ff91fedc 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -3936,20 +3936,28 @@ 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

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

[Suraj Kandpal]

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.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 6 +++---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 2 +-
 include/drm/display/drm_dp_helper.h     | 2 +-
 3 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 bbe3ff91fedc..0a2ec1147006 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4020,7 +4020,7 @@ 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;
@@ -4055,7 +4055,7 @@ int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct drm_edp_backli
 		return ret < 0 ? ret : -EIO;
 	}
 
-	ret = drm_edp_backlight_set_level(aux, bl, (u32)level);
+	ret = drm_edp_backlight_set_level(aux, bl, level);
 	if (ret < 0)
 		return ret;
 	ret = drm_edp_backlight_set_enable(aux, bl, true);
@@ -4331,7 +4331,7 @@ static int dp_aux_backlight_update_status(struct backlight_device *bd)
 
 	if (!backlight_is_blank(bd)) {
 		if (!bl->enabled) {
-			drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
+			drm_edp_backlight_enable(bl->aux, &bl->info, (u32)brightness);
 			bl->enabled = true;
 			return 0;
 		}
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 725331638a15..c9b3cac47e17 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1829,7 +1829,7 @@ 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);
+						 (u32)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 6bce0176efd3..b6c03d3ca6c3 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -855,7 +855,7 @@ 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

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

[Suraj Kandpal]

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

Signed-off-by: Suraj Kandpal <suraj.kandpal@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 0a2ec1147006..b204ed48976d 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4030,6 +4030,9 @@ 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

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

[Suraj Kandpal]

Now that drm_edp_backlight init has been to be able to setup
brightness manipulation via luminance we can just use that.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 .../drm/i915/display/intel_dp_aux_backlight.c | 100 +++++++++---------
 1 file changed, 49 insertions(+), 51 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 72cdb6b499c0..509f3992c9c8 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -585,9 +585,36 @@ 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, panel->vbt.backlight.pwm_freq_hz,
+				     intel_dp->edp_dpcd, &current_level, &current_mode, true);
+	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.luminance_set ||
+	    !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;
@@ -596,57 +623,28 @@ static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector,
 		panel->backlight.level = intel_dp_aux_vesa_get_backlight(connector, 0);
 		panel->backlight.enabled = panel->backlight.level != 0;
 		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, 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;
-			}
+		    "[CONNECTOR:%d:%s] AUX VESA Nits backlight level is controlled through DPCD\n",
+		    connector->base.base.id, connector->base.name);
+	} 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

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

[Suraj Kandpal]

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@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 509f3992c9c8..0cd9fd72ebbb 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -476,31 +476,6 @@ 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)
 {
@@ -508,11 +483,6 @@ 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);
 
@@ -538,7 +508,9 @@ 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

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

[Suraj Kandpal]

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@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 0cd9fd72ebbb..57782697144e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -499,20 +499,6 @@ 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

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

[Suraj Kandpal]

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@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 luminance range info 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       |  88 ++++++++---
 .../drm/i915/display/intel_dp_aux_backlight.c | 143 ++++++------------
 drivers/gpu/drm/nouveau/dispnv50/disp.c       |   2 +-
 drivers/gpu/drm/nouveau/nouveau_backlight.c   |   9 +-
 include/drm/display/drm_dp_helper.h           |  10 +-
 5 files changed, 126 insertions(+), 126 deletions(-)

-- 
2.34.1

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

[Suraj Kandpal]

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@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 bb1242a1bf6b..c4c52fb37191 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -3933,7 +3933,7 @@ 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 62be80417ded..6bce0176efd3 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -853,7 +853,7 @@ 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

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

[Murthy, Arun R]

> -----Original Message-----
> From: Kandpal, Suraj <suraj.kandpal@intel.com>
> Sent: Monday, April 14, 2025 9:47 AM
> To: nouveau@lists.freedesktop.org; dri-devel@lists.freedesktop.org; intel-
> xe@lists.freedesktop.org; intel-gfx@lists.freedesktop.org
> Cc: Nautiyal, Ankit K <ankit.k.nautiyal@intel.com>; Murthy, Arun R
> <arun.r.murthy@intel.com>; Kandpal, Suraj <suraj.kandpal@intel.com>
> Subject: [PATCH 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@intel.com>
> ---
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>

Thanks and Regards,
Arun R Murthy
--------------------

>  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 bb1242a1bf6b..c4c52fb37191 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -3933,7 +3933,7 @@
> 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 62be80417ded..6bce0176efd3 100644
> --- a/include/drm/display/drm_dp_helper.h
> +++ b/include/drm/display/drm_dp_helper.h
> @@ -853,7 +853,7 @@ 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

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

[Suraj Kandpal]

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@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 luminance range info 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       |  88 ++++++++---
 .../drm/i915/display/intel_dp_aux_backlight.c | 143 ++++++------------
 drivers/gpu/drm/nouveau/dispnv50/disp.c       |   2 +-
 drivers/gpu/drm/nouveau/nouveau_backlight.c   |   9 +-
 include/drm/display/drm_dp_helper.h           |  10 +-
 5 files changed, 126 insertions(+), 126 deletions(-)

-- 
2.34.1

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

[Suraj Kandpal]

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@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 0c90f161bf4d..b17f9e75d93f 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -3933,7 +3933,7 @@ 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 8acc20a3b80a..88b858048746 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -853,7 +853,7 @@ 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

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

[Kandpal, Suraj]

> -----Original Message-----
> From: Kandpal, Suraj <suraj.kandpal@intel.com>
> Sent: Friday, May 9, 2025 10:48 AM
> To: nouveau@lists.freedesktop.org; dri-devel@lists.freedesktop.org; intel-
> xe@lists.freedesktop.org; intel-gfx@lists.freedesktop.org
> Cc: Nautiyal, Ankit K <ankit.k.nautiyal@intel.com>; Murthy, Arun R
> <arun.r.murthy@intel.com>; Kandpal, Suraj <suraj.kandpal@intel.com>
> Subject: [PATCH 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]
> 

Ping Arun
> Signed-off-by: Suraj Kandpal <suraj.kandpal@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 0c90f161bf4d..b17f9e75d93f 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -3933,7 +3933,7 @@
> 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 8acc20a3b80a..88b858048746 100644
> --- a/include/drm/display/drm_dp_helper.h
> +++ b/include/drm/display/drm_dp_helper.h
> @@ -853,7 +853,7 @@ 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