[Intel-gfx] [PATCH v8 3/5] drm/i915: Add option to support dynamic backlight via DPCD

[Puthikorn Voravootivat]

Hi Dhinakaran,

Quick question

So what is the update about adding new option in i915_params?
Is this patch good to go after fixing the 2 points you mentioned?

Thanks

On Wed, May 17, 2017 at 1:33 PM, Pandiyan, Dhinakaran <
dhinakaran.pandiyan at intel.com> wrote:

> On Tue, 2017-05-16 at 17:34 -0700, Puthikorn Voravootivat wrote:
> > This patch adds option to enable dynamic backlight for eDP
> > panel that supports this feature via DPCD register and
> > set minimum / maximum brightness to 0% and 100% of the
> > normal brightness.
> >
> > Signed-off-by: Puthikorn Voravootivat <puthik at chromium.org>
> > ---
> >  drivers/gpu/drm/i915/i915_params.c            |  5 ++++
> >  drivers/gpu/drm/i915/i915_params.h            |  3 +-
> >  drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 40
> +++++++++++++++++++++++----
> >  3 files changed, 41 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_params.c
> b/drivers/gpu/drm/i915/i915_params.c
> > index 13cf3f1572ab..6eaf660e74da 100644
> > --- a/drivers/gpu/drm/i915/i915_params.c
> > +++ b/drivers/gpu/drm/i915/i915_params.c
> > @@ -65,6 +65,7 @@ struct i915_params i915 __read_mostly = {
> >       .inject_load_failure = 0,
> >       .enable_dpcd_backlight = -1,
> >       .enable_gvt = false,
> > +     .enable_dbc = false,
> >  };
> >
> >  module_param_named(modeset, i915.modeset, int, 0400);
> > @@ -255,3 +256,7 @@ MODULE_PARM_DESC(enable_dpcd_backlight,
> >  module_param_named(enable_gvt, i915.enable_gvt, bool, 0400);
> >  MODULE_PARM_DESC(enable_gvt,
> >       "Enable support for Intel GVT-g graphics virtualization host
> support(default:false)");
> > +
> > +module_param_named(enable_dbc, i915.enable_dbc, bool, 0600);
> > +MODULE_PARM_DESC(enable_dbc,
> > +     "Enable support for dynamic backlight control (default:false)");
> > diff --git a/drivers/gpu/drm/i915/i915_params.h
> b/drivers/gpu/drm/i915/i915_params.h
> > index ac02efce6e22..2de3e2850b54 100644
> > --- a/drivers/gpu/drm/i915/i915_params.h
> > +++ b/drivers/gpu/drm/i915/i915_params.h
> > @@ -67,7 +67,8 @@
> >       func(bool, nuclear_pageflip); \
> >       func(bool, enable_dp_mst); \
> >       func(int, enable_dpcd_backlight); \
> > -     func(bool, enable_gvt)
> > +     func(bool, enable_gvt); \
> > +     func(bool, enable_dbc)
> >
> >  #define MEMBER(T, member) T member
> >  struct i915_params {
> > diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> > index 16ba1924308d..c0eeb8fc2013 100644
> > --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> > +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> > @@ -100,10 +100,27 @@ intel_dp_aux_set_backlight(struct intel_connector
> *connector, u32 level)
> >       }
> >  }
> >
> > +/*
> > + * Set minimum / maximum dynamic brightness percentage. This value is
> expressed
> > + * as the percentage of normal brightness in 5% increments.
> > + */
> > +static void
> > +intel_dp_aux_set_dynamic_backlight_percent(struct intel_dp *intel_dp,
> > +                                        u32 min, u32 max)
> > +{
> > +     u8 dbc[] = { DIV_ROUND_CLOSEST(min, 5), DIV_ROUND_CLOSEST(max, 5)
> };
> > +
> > +     if (drm_dp_dpcd_write(&intel_dp->aux,
> DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET,
> > +                       dbc, sizeof(dbc) < 0)) {
>
> Incorrect parentheses placement and return value check.
>
> > +             DRM_DEBUG_KMS("Failed to write aux DBC brightness
> level\n");
> > +     }
> > +}
> > +
> >  static void intel_dp_aux_enable_backlight(struct intel_connector
> *connector)
> >  {
> >       struct intel_dp *intel_dp = enc_to_intel_dp(&connector->
> encoder->base);
> >       uint8_t dpcd_buf = 0;
> > +     uint8_t new_dpcd_buf = 0;
>
> nit: unnecessary initialization.
>
> >       uint8_t edp_backlight_mode = 0;
> >
> >       if (drm_dp_dpcd_readb(&intel_dp->aux,
> > @@ -113,18 +130,15 @@ static void intel_dp_aux_enable_backlight(struct
> intel_connector *connector)
> >               return;
> >       }
> >
> > +     new_dpcd_buf = dpcd_buf;
> >       edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_
> MASK;
> >
> >       switch (edp_backlight_mode) {
> >       case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
> >       case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
> >       case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
> > -             dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> > -             dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
> > -             if (drm_dp_dpcd_writeb(&intel_dp->aux,
> > -                     DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf) <
> 0) {
> > -                     DRM_DEBUG_KMS("Failed to write aux backlight
> mode\n");
> > -             }
> > +             new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> > +             new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
> >               break;
> >
> >       /* Do nothing when it is already DPCD mode */
> > @@ -133,6 +147,20 @@ static void intel_dp_aux_enable_backlight(struct
> intel_connector *connector)
> >               break;
> >       }
> >
> > +     if (i915.enable_dbc &&
> > +         (intel_dp->edp_dpcd[2] & DP_EDP_DYNAMIC_BACKLIGHT_CAP)) {
> > +             new_dpcd_buf |= DP_EDP_DYNAMIC_BACKLIGHT_ENABLE;
> > +             intel_dp_aux_set_dynamic_backlight_percent(intel_dp, 0,
> 100);
> > +             DRM_DEBUG_KMS("Enable dynamic brightness.\n");
> > +     }
> > +
> > +     if (new_dpcd_buf != dpcd_buf) {
> > +             if (drm_dp_dpcd_writeb(&intel_dp->aux,
> > +                     DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf)
> < 0) {
> > +                     DRM_DEBUG_KMS("Failed to write aux backlight
> mode\n");
> > +             }
> > +     }
> > +
> >       set_aux_backlight_enable(intel_dp, true);
> >       intel_dp_aux_set_backlight(connector, connector->panel.backlight.
> level);
> >  }
>
>
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