> -----Original Message-----
> From: Aaron Ma <[email protected]>
> Sent: Friday, September 26, 2025 3:23 PM
> To: Kandpal, Suraj <[email protected]>
> Cc: [email protected]; [email protected]; linux-
> [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; Vivi, Rodrigo
> <[email protected]>; Deak, Imre <[email protected]>;
> [email protected]
> Subject: Re: [PATCH 2/2] drm/i915/backlight: Add get brightness support of
> DPCD via AUX
> 
> On Fri, Sep 26, 2025 at 5:26 PM Kandpal, Suraj <[email protected]>
> wrote:
> >
> > > Subject: [PATCH 2/2] drm/i915/backlight: Add get brightness support
> > > of DPCD via AUX
> > >
> > > Use drm common helper to read brightness from both luminance and AUX
> > > mode to support get_brightness from DPCD via AUX.
> > >
> > > Signed-off-by: Aaron Ma <[email protected]>
> > > ---
> > >  .../drm/i915/display/intel_dp_aux_backlight.c | 20
> > > ++++++-------------
> > >  1 file changed, 6 insertions(+), 14 deletions(-)
> > >
> > > 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 0a3a3f6a5f9d8..0ee6fd0f41ef0 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> > > @@ -454,24 +454,16 @@ static u32
> > > intel_dp_aux_vesa_get_backlight(struct
> > > intel_connector *connector, en  {
> > >       struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
> > >       struct intel_panel *panel = &connector->panel;
> > > -     u8 buf[3];
> > > -     u32 val = 0;
> > > -     int ret;
> > >
> > > -     if (panel->backlight.edp.vesa.luminance_control_support) {
> > > -             ret = drm_dp_dpcd_read(&intel_dp->aux,
> > > DP_EDP_PANEL_TARGET_LUMINANCE_VALUE, buf,
> > > -                                    sizeof(buf));
> > > -             if (ret < 0) {
> > > -                     drm_err(intel_dp->aux.drm_dev,
> > > -                             "[CONNECTOR:%d:%s] Failed to read
> > > Luminance from DPCD\n",
> > > -                             connector->base.base.id, connector-
> > > >base.name);
> > > -                     return 0;
> > > -             }
> > > +     if (!panel->backlight.edp.vesa.info.aux_set) {
> > > +             u32 pwm_level =
> > > + panel->backlight.pwm_funcs->get(connector,
> > > unused);
> > >
> > > -             val |= buf[0] | buf[1] << 8 | buf[2] << 16;
> > > -             return val / 1000;
> > > +             return intel_backlight_level_from_pwm(connector,
> > > pwm_level);
> > >       }
> > >
> > > +     connector->panel.backlight.level =
> > > +             drm_edp_backlight_get_level(&intel_dp->aux,
> > > +&panel->backlight.edp.vesa.info);
> > > +
> >
> > Just call the intel_dp_aux_vesa_get_backlight here and call the
> > drm_edp_backlight get level in there
> >
> 
> Do you mean no call of  pwm get?
> 
> I thought it should be aligned with set_level when aux_set == 0.

I misunderstood the code here its as it should be the diff just made it seem 
weird

Regards,
Suraj Kandpal

> 
> Thanks,
> Aaron
> 
> > Regards,
> > Suraj Kandpal
> >
> >
> > >       return connector->panel.backlight.level;  }
> > >
> > > --
> > > 2.43.0
> >

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