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

[Murthy, Arun R]

> > -----Original Message-----
> > From: Murthy, Arun R <arun.r.murthy at intel.com>
> > Sent: Thursday, June 12, 2025 4:43 PM
> > 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.
> > >
> > The main intention for this ask is two xx_info struct passed as argument.
> > Moreover luminance is part of backlight and this new element is _info
> > and there already exists backlight_info. So wondering is luminance can
> > be put inside backlight_info. The caller of this function can fill the
> > luminance part and then make a call.
> >
> 
> I see you point but the thing is luminance range is not something we will be
> using later and is only used the set the max level of brightness that can be set.
> That being said I do get your point on sending two xx_info struct here, I was
> thinking we send only the
> U32 max luminance here since that's the only one we actually use. Drivers can
> send the max luminance they like.
> What do you think?
> 
That should be better! 4th patch can be squashed with this one.

Thanks and Regards,
Arun R Murthy
--------------------
> Regards,
> Suraj Kandpal
> 
> > Thanks and Regards,
> > Arun R Murthy
> > --------------------