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

[Lyude Paul]

Hm. Could you share some logs with drm.debug=0x116? I'm a bit confused
because I would have thought that we were already probing for eDP
backlights seeing as I added support for them at one point?

(I hope this isn't the point I learn I actually forgot to add support
for them :P)


On Fri, 2024-04-12 at 21:49 +0200, Angelo Dureghello wrote:
> 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;

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat