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

[Kandpal, Suraj]

> -----Original Message-----
> From: Murthy, Arun R <arun.r.murthy at intel.com>
> Sent: Thursday, June 12, 2025 11:45 AM
> To: Kandpal, Suraj <suraj.kandpal at intel.com>;
> 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>
> Subject: RE: [PATCH 03/13] drm/dp: Add argument for luminance range info in
> drm_edp_backlight_init
> 
> > -----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 03/13] drm/dp: Add argument for luminance range info
> > in drm_edp_backlight_init
> >
> > 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 at 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,
> Would it be better to have this drm_luminance_range_info inside the
> drm_edp_backlight_info?

The thing is we fill drm_edp_backlight_info struct in drm_edp_backlight_init
Which means we would have to pass it anyways. So having a reference of this in
drm_edp_backlight_info didn't make sense.

Regards,
Suraj Kandpal

> 
> Thanks and Regards,
> Arun R Murthy
> --------------------
> 
> >  		       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 d658e77b43d8..abb5ad4eef5f 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