[Intel-gfx] [PATCH 21/22] drm/i915: BDW: Pipe level degamma correction

[Emil Velikov]

Hi Shashank,

On 9 October 2015 at 20:29, Shashank Sharma <shashank.sharma at intel.com> wrote:
> BDW/SKL/BXT supports Degamma color correction feature, which
> linearizes the non-linearity due to gamma encoded color values.
> This will be applied before Color Transformation.
>
> This patch does the following:
> 1. Adds the core function to program DeGamma correction values for
>    BDW/SKL/BXT platform
> 2. Adds DeGamma correction macros/defines
>
> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> Signed-off-by: Kausal Malladi <kausalmalladi at gmail.com>
> ---
>  drivers/gpu/drm/i915/intel_color_manager.c | 59 ++++++++++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_color_manager.c b/drivers/gpu/drm/i915/intel_color_manager.c
> index 74f8fc3..e659382 100644
> --- a/drivers/gpu/drm/i915/intel_color_manager.c
> +++ b/drivers/gpu/drm/i915/intel_color_manager.c
> @@ -273,6 +273,63 @@ static int bdw_set_gamma(struct drm_device *dev, struct drm_property_blob *blob,
>         return 0;
>  }
>
> +static int bdw_set_degamma(struct drm_device *dev,
> +       struct drm_property_blob *blob, struct drm_crtc *crtc)
> +{
> +       enum pipe pipe;
> +       int num_samples, length;
> +       u32 index, mode;
> +       u32 pal_prec_index, pal_prec_data;
> +       struct drm_palette *degamma_data;
> +       struct drm_crtc_state *state = crtc->state;
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +       struct drm_r32g32b32 *correction_values = NULL;
> +
> +       if (WARN_ON(!blob))
> +               return -EINVAL;
> +
> +       degamma_data = (struct drm_palette *)blob->data;
> +       pipe = to_intel_crtc(crtc)->pipe;
> +       num_samples = degamma_data->num_samples;
> +
> +       if (num_samples == GAMMA_DISABLE_VALS) {
> +               /* Disable degamma on Pipe */
> +               mode = I915_READ(GAMMA_MODE(pipe)) & ~GAMMA_MODE_MODE_MASK;
> +               I915_WRITE(GAMMA_MODE(pipe), mode | GAMMA_MODE_MODE_8BIT);
> +
> +               state->palette_before_ctm_blob = NULL;
> +               DRM_DEBUG_DRIVER("Disabling degamma on Pipe %c\n",
> +               pipe_name(pipe));
> +               return 0;
> +       }
> +
> +       if (num_samples != BDW_SPLITGAMMA_MAX_VALS) {
> +               DRM_ERROR("Invalid number of samples\n");
> +               return -EINVAL;
> +       }
> +
Why don't you use switch statement here ?

> +       length = num_samples * sizeof(struct drm_r32g32b32);
> +       mode = I915_READ(GAMMA_MODE(pipe));
> +       pal_prec_index = _PREC_PAL_INDEX(pipe);
> +       pal_prec_data = _PREC_PAL_DATA(pipe);
> +
> +       correction_values = (struct drm_r32g32b32 *)&degamma_data->lut;
> +       index = I915_READ(pal_prec_index);
> +       index |= BDW_INDEX_AUTO_INCREMENT | BDW_INDEX_SPLIT_MODE;
> +       I915_WRITE(pal_prec_index, index);
> +
> +       bdw_write_10bit_gamma_precision(dev, correction_values,
> +               pal_prec_data, BDW_SPLITGAMMA_MAX_VALS);
> +
> +       /* Enable DeGamma on Pipe */
> +       mode &= ~GAMMA_MODE_MODE_MASK;
> +       I915_WRITE(GAMMA_MODE(pipe), mode | GAMMA_MODE_MODE_SPLIT);
> +       DRM_DEBUG_DRIVER("DeGamma correction enabled on Pipe %c\n",
> +       pipe_name(pipe));
Indentation seems funny here.

Regards,
Emil