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

[Murthy, Arun R]

> -----Original Message-----
> From: Kandpal, Suraj <suraj.kandpal at intel.com>
> Sent: Monday, April 14, 2025 9:46 AM
> To: nouveau at lists.freedesktop.org; dri-devel at lists.freedesktop.org; intel-
> xe at lists.freedesktop.org; intel-gfx at lists.freedesktop.org
> Cc: Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>; Murthy, Arun R
> <arun.r.murthy at intel.com>; Kandpal, Suraj <suraj.kandpal at intel.com>
> Subject: [PATCH 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>

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

>  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