[PATCH v2 1/2] drm/nouveau/disp: add backlight for ada lovelace

Angelo Dureghello angelo at kernel-space.org
Fri Apr 12 19:49:00 UTC 2024


Add working backlight for "ada lovelace" missing case.

The nvif method is actually not working for this chipset so
used the drm apis. Also, by dpcd, drm layer is calculating a
max brightness of 255, but to get a real correct max brightnes
the maximum must be multiplied by a factor of 16.

Tested to work properly in Legion Lenovo Pro 5

Lenovo Legion 5 Pro 16ARX8
Bios ver LPCN49WW
	 LPEC49WW
SN PF4T63AZ
Nvidia RTX4060 MaxQ/Mobile rev a1 (ADA LOVELACE AD107M)
AMD Ryzen 9 7945HX + Radeon

and wayland.

---
Changes for v2:
- add some comments
- remove x16 multiplication (hack)
- remove forgot debug printk

Signed-off-by: Angelo Dureghello <angelo at kernel-space.org>
---
 drivers/gpu/drm/nouveau/nouveau_backlight.c | 54 +++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c b/drivers/gpu/drm/nouveau/nouveau_backlight.c
index d47442125fa1..7b7306d18ad7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c
@@ -286,6 +286,56 @@ nv50_backlight_init(struct nouveau_backlight *bl,
 	return 0;
 }
 
+static int
+nv19x_backlight_init(struct nouveau_backlight *bl,
+		     struct nouveau_connector *nv_conn,
+		     struct nouveau_encoder *nv_encoder,
+		     struct backlight_properties *props,
+		     const struct backlight_ops **ops)
+{
+	int ret;
+	u16 current_level;
+	u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
+	u8 current_mode;
+	struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
+
+	/*
+	 * nvif functions, so also nvif_outp_bl_get, are not working with this
+	 * connector (return -22), using only drm layer.
+	 */
+	if (nv_conn->type == DCB_CONNECTOR_eDP) {
+
+		ret = drm_dp_dpcd_read(&nv_conn->aux, DP_EDP_DPCD_REV, edp_dpcd,
+				       EDP_DISPLAY_CTL_CAP_SIZE);
+		if (ret < 0)
+			return ret;
+		if (!drm_edp_backlight_supported(edp_dpcd))
+			return -ENODEV;
+
+		ret = drm_edp_backlight_init(&nv_conn->aux, &bl->edp_info, 0, edp_dpcd,
+					 &current_level, &current_mode);
+		if (ret < 0)
+			return ret;
+
+		ret = drm_edp_backlight_enable(&nv_conn->aux, &bl->edp_info, current_level);
+		if (ret < 0) {
+			NV_ERROR(drm, "Failed to enable backlight on %s: %d\n",
+				 nv_conn->base.name, ret);
+			return ret;
+		}
+
+		*ops = &nv50_edp_bl_ops;
+
+		props->max_brightness = bl->edp_info.max;
+		props->brightness = current_level;
+		bl->uses_dpcd = true;
+
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
 int
 nouveau_backlight_init(struct drm_connector *connector)
 {
@@ -332,6 +382,10 @@ nouveau_backlight_init(struct drm_connector *connector)
 		ret = nv50_backlight_init(bl, nouveau_connector(connector),
 					  nv_encoder, &props, &ops);
 		break;
+	case NV_DEVICE_INFO_V0_ADA:
+		ret = nv19x_backlight_init(bl, nouveau_connector(connector),
+					   nv_encoder, &props, &ops);
+		break;
 	default:
 		ret = 0;
 		goto fail_alloc;
-- 
2.44.0



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