Re: [i-g-t 12/14] kms_color_helper: Add helper functions to support logarithmic gamma mode

[Harry Wentland <harry.wentland@amd.com>]

On 2021-11-15 04:47, Bhanuprakash Modem wrote:
> From: Mukunda Pramodh Kumar <mukunda.pramodh.kumar@intel.com>
> 
> Add helper functions to support logarithmic gamma mode
> 
> Cc: Harry Wentland <harry.wentland@amd.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
> Cc: Uma Shankar <uma.shankar@intel.com>
> Signed-off-by: Mukunda Pramodh Kumar <mukunda.pramodh.kumar@intel.com>
> Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
> ---
>  tests/kms_color_helper.c | 127 +++++++++++++++++++++++++++++++++++++++
>  tests/kms_color_helper.h |  16 +++++
>  2 files changed, 143 insertions(+)
> 
> diff --git a/tests/kms_color_helper.c b/tests/kms_color_helper.c
> index c65b7a0f50..7ea8282df3 100644
> --- a/tests/kms_color_helper.c
> +++ b/tests/kms_color_helper.c
> @@ -190,6 +190,33 @@ struct drm_color_lut *coeffs_to_lut(data_t *data,
>  	return lut;
>  }
>  
> +struct drm_color_lut *coeffs_to_logarithmic_lut(data_t *data,
> +						const gamma_lut_t *gamma,
> +						uint32_t color_depth,
> +						int off)

How does this create a logarithmic LUT? It seems to do the same
as coeffs_to_lut (which is also full of intellisms) except that
it also scales the values by max_hw_value / max_segment_value for
reasons that are not obvious to me.

> +{
> +	struct drm_color_lut *lut;
> +	int i, lut_size = gamma->size;
> +	/* This is the maximum value due to 16 bit precision in hardware. */
> +	uint32_t max_hw_value = (1 << 16) - 1;
> +	unsigned int max_segment_value = 1 << 24;
> +


This looks like it is specific to Intel HW. Intel-specific things should
not live in kms_ tests.

Shouldn't these be encoded in the drm_color_lut_range definitions?

To be honest I am not clear why max_hw_value and max_segment_value
differ here.

Harry

> +	lut = malloc(sizeof(struct drm_color_lut) * lut_size);
> +
> +	for (i = 0; i < lut_size; i++) {
> +		double scaling_factor = (double)max_hw_value / (double)max_segment_value;
> +		uint32_t r = MIN((gamma->coeffs[i].r * scaling_factor), max_hw_value);
> +		uint32_t g = MIN((gamma->coeffs[i].g * scaling_factor), max_hw_value);
> +		uint32_t b = MIN((gamma->coeffs[i].b * scaling_factor), max_hw_value);
> +
> +		lut[i].red = r;
> +		lut[i].green = g;
> +		lut[i].blue = b;
> +	}
> +
> +	return lut;
> +}
> +
>  void set_degamma(data_t *data,
>  		 igt_pipe_t *pipe,
>  		 const gamma_lut_t *gamma)
> @@ -203,6 +230,15 @@ void set_degamma(data_t *data,
>  	free(lut);
>  }
>  
> +void set_pipe_gamma(igt_pipe_t *pipe,
> +		    uint64_t value,
> +		    struct drm_color_lut *lut,
> +		    uint32_t size)
> +{
> +	igt_pipe_obj_set_prop_value(pipe, IGT_CRTC_GAMMA_MODE, value);
> +	igt_pipe_obj_replace_prop_blob(pipe, IGT_CRTC_GAMMA_LUT, lut, size);
> +}
> +
>  void set_gamma(data_t *data,
>  	       igt_pipe_t *pipe, const gamma_lut_t *gamma)
>  {
> @@ -241,6 +277,51 @@ void disable_prop(igt_pipe_t *pipe, enum igt_atomic_crtc_properties prop)
>  		igt_pipe_obj_replace_prop_blob(pipe, prop, NULL, 0);
>  }
>  
> +drmModePropertyPtr get_pipe_gamma_degamma_mode(igt_pipe_t *pipe,
> +					       enum igt_atomic_crtc_properties prop)
> +{
> +	igt_display_t *display = pipe->display;
> +	uint32_t prop_id = pipe->props[prop];
> +	drmModePropertyPtr drmProp;
> +
> +	igt_assert(prop_id);
> +
> +	drmProp = drmModeGetProperty(display->drm_fd, prop_id);
> +
> +	igt_assert(drmProp);
> +	igt_assert(drmProp->count_enums);
> +
> +	return drmProp;
> +}
> +
> +gamma_lut_t *pipe_create_linear_lut(segment_data_t *info)
> +{
> +	uint32_t segment, entry, index = 0;
> +	double val;
> +	int i = 0;
> +	gamma_lut_t *gamma = alloc_lut(info->entries_count);
> +
> +	igt_assert(gamma);
> +
> +	gamma->size = info->entries_count;
> +	for (segment = 0; segment < info->segment_count; segment++) {
> +		uint32_t entry_count = info->segment_data[segment].count;
> +		uint32_t start = (segment == 0) ? 0 : (1 << (segment - 1));
> +		uint32_t end = 1 << segment;
> +
> +		for (entry = 0; entry < entry_count; entry++) {
> +			val = (index == 0) ? /* First entry is Zero. */
> +				0 : start + entry *
> +				((end - start) * 1.0 / entry_count);
> +
> +			set_rgb(&gamma->coeffs[i++], val);
> +			index++;
> +		}
> +	}
> +
> +	return gamma;
> +}
> +
>  drmModePropertyPtr get_plane_gamma_degamma_mode(igt_plane_t *plane,
>  				enum igt_atomic_plane_properties prop)
>  {
> @@ -331,6 +412,7 @@ segment_data_t *get_segment_data(data_t *data,
>  	info->segment_data = malloc(sizeof(struct drm_color_lut_range) * info->segment_count);
>  	igt_assert(info->segment_data);
>  
> +	info->entries_count = 0;
>  	for (i = 0; i < info->segment_count; i++) {
>  		info->entries_count += lut_range[i].count;
>  		info->segment_data[i] = lut_range[i];
> @@ -341,6 +423,51 @@ segment_data_t *get_segment_data(data_t *data,
>  	return info;
>  }
>  
> +void set_advance_gamma(data_t *data, igt_pipe_t *pipe, enum gamma_type type)
> +{
> +	igt_display_t *display = &data->display;
> +	gamma_lut_t *gamma_log;
> +	drmModePropertyPtr gamma_mode = NULL;
> +	segment_data_t *segment_info = NULL;
> +	struct drm_color_lut *lut = NULL;
> +	int lut_size = 0;
> +
> +	drmSetClientCap(data->drm_fd, DRM_CLIENT_CAP_ADVANCE_GAMMA_MODES, 1);
> +	gamma_mode = get_pipe_gamma_degamma_mode(pipe, IGT_CRTC_GAMMA_MODE);
> +
> +	for (int i = 0; i < gamma_mode->count_enums; i++) {
> +		if (!strcmp(gamma_mode->enums[i].name, "logarithmic gamma")) {
> +			segment_info = get_segment_data(data,
> +							gamma_mode->enums[i].value,
> +							gamma_mode->enums[i].name);
> +			lut_size = sizeof(struct drm_color_lut) *
> +					  segment_info->entries_count;
> +			if (type == LINEAR_GAMMA) {
> +				gamma_log = pipe_create_linear_lut(segment_info);
> +				lut = coeffs_to_logarithmic_lut(data,
> +								gamma_log,
> +								data->color_depth,
> +								0);
> +			} else if (type == MAX_GAMMA) {
> +				gamma_log = generate_table_max(segment_info->entries_count);
> +				gamma_log->size = segment_info->entries_count;
> +				lut = coeffs_to_lut(data, gamma_log,
> +						    data->color_depth, 0);
> +			}
> +			set_pipe_gamma(pipe, gamma_mode->enums[i].value,
> +				       lut, lut_size);
> +			igt_display_commit2(display, display->is_atomic
> +					    ? COMMIT_ATOMIC : COMMIT_LEGACY);
> +			break;
> +		}
> +	}
> +	drmSetClientCap(data->drm_fd, DRM_CLIENT_CAP_ADVANCE_GAMMA_MODES, 0);
> +	free(gamma_log);
> +	free(lut);
> +	clear_segment_data(segment_info);
> +	drmModeFreeProperty(gamma_mode);
> +}
> +
>  void set_plane_gamma(igt_plane_t *plane,
>  		char *mode,
>  		struct drm_color_lut_ext *lut,
> diff --git a/tests/kms_color_helper.h b/tests/kms_color_helper.h
> index 5a35dcaac1..c863874f0c 100644
> --- a/tests/kms_color_helper.h
> +++ b/tests/kms_color_helper.h
> @@ -70,6 +70,11 @@ typedef struct {
>  	uint32_t entries_count;
>  } segment_data_t;
>  
> +enum gamma_type {
> +	LINEAR_GAMMA,
> +	MAX_GAMMA
> +};
> +
>  #define MIN(a, b) ((a) < (b) ? (a) : (b))
>  
>  void paint_gradient_rectangles(data_t *data,
> @@ -89,6 +94,10 @@ struct drm_color_lut *coeffs_to_lut(data_t *data,
>  				    const gamma_lut_t *gamma,
>  				    uint32_t color_depth,
>  				    int off);
> +struct drm_color_lut *coeffs_to_logarithmic_lut(data_t *data,
> +						const gamma_lut_t *gamma,
> +						uint32_t color_depth,
> +						int off);
>  void set_degamma(data_t *data,
>  		 igt_pipe_t *pipe,
>  		 const gamma_lut_t *gamma);
> @@ -98,12 +107,19 @@ void set_gamma(data_t *data,
>  void set_ctm(igt_pipe_t *pipe, const double *coefficients);
>  void disable_prop(igt_pipe_t *pipe, enum igt_atomic_crtc_properties prop);
>  
> +drmModePropertyPtr get_pipe_gamma_degamma_mode(igt_pipe_t *pipe,
> +					       enum igt_atomic_crtc_properties
> +					       prop);
>  drmModePropertyPtr get_plane_gamma_degamma_mode(igt_plane_t *plane,
>  	enum igt_atomic_plane_properties prop);
>  void clear_segment_data(segment_data_t *info);
> +gamma_lut_t *pipe_create_linear_lut(segment_data_t *info);
>  struct drm_color_lut_ext *create_linear_lut(segment_data_t *info);
>  struct drm_color_lut_ext *create_max_lut(segment_data_t *info);
>  segment_data_t *get_segment_data(data_t *data, uint64_t blob_id, char *mode);
> +void set_pipe_gamma(igt_pipe_t *pipe, uint64_t value,
> +		    struct drm_color_lut *lut, uint32_t size);
> +void set_advance_gamma(data_t *data, igt_pipe_t *pipe, enum gamma_type type);
>  void set_plane_gamma(igt_plane_t *plane,
>  	char *mode, struct drm_color_lut_ext *lut, uint32_t size);
>  void set_plane_degamma(igt_plane_t *plane,
>