[PATCH] drm: Add optional COLOR_ENCODING and COLOR_RANGE properties to drm_plane

Jyri Sarha jsarha at ti.com
Tue Feb 6 18:16:56 UTC 2018


I have not been following the subject for half a year now. Just let me
know if I can do something to help land this patch, e.g. rebase and
resend it.


On 02/06/18 20:08, Hans Verkuil wrote:
> On 02/06/2018 06:58 PM, Ville Syrjälä wrote:
>> On Mon, Jun 12, 2017 at 12:10:04AM +0300, Jyri Sarha wrote:
>>> Add a standard optional properties to support different non RGB color
>>> encodings in DRM planes. COLOR_ENCODING select the supported non RGB
>>> color encoding, for instance ITU-R BT.709 YCbCr. COLOR_RANGE selects
>>> the value ranges within the selected color encoding. The properties
>>> are stored to drm_plane object to allow different set of supported
>>> encoding for different planes on the device.
>>>
>>> Signed-off-by: Jyri Sarha <jsarha at ti.com>
>>> ---
>>>  drivers/gpu/drm/drm_atomic.c     |  8 ++++
>>>  drivers/gpu/drm/drm_color_mgmt.c | 91 ++++++++++++++++++++++++++++++++++++++++
>>>  include/drm/drm_color_mgmt.h     | 19 +++++++++
>>>  include/drm/drm_plane.h          |  8 ++++
>>>  4 files changed, 126 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>>> index 77dcef0..8067681 100644
>>> --- a/drivers/gpu/drm/drm_atomic.c
>>> +++ b/drivers/gpu/drm/drm_atomic.c
>>> @@ -786,6 +786,10 @@ int drm_atomic_plane_set_property(struct drm_plane *plane,
>>>  		state->rotation = val;
>>>  	} else if (property == plane->zpos_property) {
>>>  		state->zpos = val;
>>> +	} else if (property == plane->color_encoding_property) {
>>> +		state->color_encoding = val;
>>> +	} else if (property == plane->color_range_property) {
>>> +		state->color_range = val;
>>>  	} else if (plane->funcs->atomic_set_property) {
>>>  		return plane->funcs->atomic_set_property(plane, state,
>>>  				property, val);
>>> @@ -846,6 +850,10 @@ int drm_atomic_plane_set_property(struct drm_plane *plane,
>>>  		*val = state->rotation;
>>>  	} else if (property == plane->zpos_property) {
>>>  		*val = state->zpos;
>>> +	} else if (property == plane->color_encoding_property) {
>>> +		*val = state->color_encoding;
>>> +	} else if (property == plane->color_range_property) {
>>> +		*val = state->color_range;
>>>  	} else if (plane->funcs->atomic_get_property) {
>>>  		return plane->funcs->atomic_get_property(plane, state, property, val);
>>>  	} else {
>>> diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
>>> index 3eda500..9077bf6 100644
>>> --- a/drivers/gpu/drm/drm_color_mgmt.c
>>> +++ b/drivers/gpu/drm/drm_color_mgmt.c
>>> @@ -88,6 +88,19 @@
>>>   * drm_mode_crtc_set_gamma_size(). Drivers which support both should use
>>>   * drm_atomic_helper_legacy_gamma_set() to alias the legacy gamma ramp with the
>>>   * "GAMMA_LUT" property above.
>>> + *
>>> + * Support for different non RGB color encodings is controlled through
>>> + * &drm_plane specific COLOR_ENCODING and COLOR_RANGE properties:
>>> + *
>>> + * "COLOR_ENCODING"
>>> + * 	Optional plane enum property to support different non RGB
>>> + * 	color encodings. The driver can provide a subset of standard
>>> + * 	enum values supported by the DRM plane.
>>> + *
>>> + * "COLOR_RANGE"
>>> + * 	Optional plane enum property to support different non RGB
>>> + * 	color parameter ranges. The driver can provide a subset of
>>> + * 	standard enum values supported by the DRM plane.
>>>   */
>>>  
>>>  /**
>>> @@ -336,3 +349,81 @@ int drm_mode_gamma_get_ioctl(struct drm_device *dev,
>>>  	drm_modeset_unlock(&crtc->mutex);
>>>  	return ret;
>>>  }
>>> +
>>> +static const char * const color_encoding_name[] = {
>>> +	[DRM_COLOR_YCBCR_BT601] = "ITU-R BT.601 YCbCr",
>>> +	[DRM_COLOR_YCBCR_BT709] = "ITU-R BT.709 YCbCr",
>>> +	[DRM_COLOR_YCBCR_BT2020] = "ITU-R BT.2020 YCbCr",
>>
>> I was just looking at this again (in the hopes of landing it finally),
>> and then I realized we probably need to split this BT.2020 into
>> constant and non-constant luminance variants.
>>
>> ..._BT2020_CL and ..._BT2020_NCL maybe?
> 
> This is what V4L2 uses:
> 
> https://hverkuil.home.xs4all.nl/spec/uapi/v4l/colorspaces-defs.html
> 
> V4L2_YCBCR_ENC_BT2020 and V4L2_YCBCR_ENC_BT2020_CONST_LUM.
> 
> I've never seen V4L2_YCBCR_ENC_BT2020_CONST_LUM in the wild. Non-constant
> Bt.2020 is what is normally used, so I'd keep the define just as-is:
> DRM_COLOR_YCBCR_BT2020. And add a DRM_COLOR_YCBCR_BT2020_CONST_LUM if
> you think you need it. I've never seen anyone use this.
> 
> And in case you wonder why: this is the BT.2020 OpenGL Y'CbCr to R'G'B'
> conversion:
> 
> 	float r = y + 1.4719 * v;
>         float g = y - 0.1646 * u - 0.5703 * v;
>         float b = y + 1.8814 * u;
> 
> And this for BT.2020 constant luminance:
> 
> 	float b = u <= 0.0 ? y + 1.9404 * u : y + 1.5816 * u;
> 	float r = v <= 0.0 ? y + 1.7184 * v : y + 0.9936 * v;
> 	float lin_r = (r < 0.081) ? r / 4.5 : pow((r + 0.099) / 1.099, 1.0 / 0.45);
> 	float lin_b = (b < 0.081) ? b / 4.5 : pow((b + 0.099) / 1.099, 1.0 / 0.45);
> 	float lin_y = (y < 0.081) ? y / 4.5 : pow((y + 0.099) / 1.099, 1.0 / 0.45);
> 	float lin_g = lin_y / 0.6780 - lin_r * 0.2627 / 0.6780 - lin_b * 0.0593 / 0.6780;
> 	float g = (lin_g < 0.018) ? lin_g * 4.5 : 1.099 * pow(lin_g, 0.45) - 0.099;
> 
> Brr :-)
> 
> Regards,
> 
> 	Hans
> 
>>
>>> +};
>>> +
>>> +static const char * const color_range_name[] = {
>>> +	[DRM_COLOR_YCBCR_FULL_RANGE] = "YCbCr full range",
>>> +	[DRM_COLOR_YCBCR_LIMITED_RANGE] = "YCbCr limited range",
>>> +};
>>> +
>>> +/**
>>> + * drm_plane_create_color_properties - color encoding related plane properties
>>> + * @supported_encodings: bitfield indicating supported color encodings
>>> + * @supported_ranges: bitfileld indicating supported color ranges
>>> + * @default_encoding: default color encoding
>>> + * @default_range: default color range
>>> + *
>>> + * Create and attach plane specific COLOR_ENCODING and COLOR_RANGE
>>> + * properties to to the drm_plane object. The supported encodings and
>>> + * ranges should be provided in supported_encodings and
>>> + * supported_ranges bitmasks. Each bit set in the bitmask indicates
>>> + * the its number as enum value being supported.
>>> + */
>>> +int drm_plane_create_color_properties(struct drm_plane *plane,
>>> +				      u32 supported_encodings,
>>> +				      u32 supported_ranges,
>>> +				      enum drm_color_encoding default_encoding,
>>> +				      enum drm_color_range default_range)
>>> +{
>>> +	struct drm_device *dev = plane->dev;
>>> +	struct drm_property *prop;
>>> +	struct drm_prop_enum_list enum_list[max(DRM_COLOR_ENCODING_MAX,
>>> +						DRM_COLOR_RANGE_MAX)];
>>> +	int i, len;
>>> +
>>> +	len = 0;
>>> +	for (i = 0; i < DRM_COLOR_ENCODING_MAX; i++) {
>>> +		if ((supported_encodings & BIT(i)) == 0)
>>> +			continue;
>>> +
>>> +		enum_list[len].type = i;
>>> +		enum_list[len].name = color_encoding_name[i];
>>> +		len++;
>>> +	}
>>> +
>>> +	prop = drm_property_create_enum(dev, 0, "COLOR_ENCODING",
>>> +					enum_list, len);
>>> +	if (!prop)
>>> +		return -ENOMEM;
>>> +	plane->color_encoding_property = prop;
>>> +	drm_object_attach_property(&plane->base, prop, default_encoding);
>>> +	if (plane->state)
>>> +		plane->state->color_encoding = default_encoding;
>>> +
>>> +	len = 0;
>>> +	for (i = 0; i < DRM_COLOR_RANGE_MAX; i++) {
>>> +		if ((supported_ranges & BIT(i)) == 0)
>>> +			continue;
>>> +
>>> +		enum_list[len].type = i;
>>> +		enum_list[len].name = color_range_name[i];
>>> +		len++;
>>> +	}
>>> +
>>> +	prop = drm_property_create_enum(dev, 0,	"COLOR_RANGE",
>>> +					enum_list, len);
>>> +	if (!prop)
>>> +		return -ENOMEM;
>>> +	plane->color_range_property = prop;
>>> +	drm_object_attach_property(&plane->base, prop, default_range);
>>> +	if (plane->state)
>>> +		plane->state->color_range = default_range;
>>> +
>>> +	return 0;
>>> +}
>>> +EXPORT_SYMBOL(drm_plane_create_color_properties);
>>> diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
>>> index 03a59cb..b3b6d30 100644
>>> --- a/include/drm/drm_color_mgmt.h
>>> +++ b/include/drm/drm_color_mgmt.h
>>> @@ -26,6 +26,7 @@
>>>  #include <linux/ctype.h>
>>>  
>>>  struct drm_crtc;
>>> +struct drm_plane;
>>>  
>>>  uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision);
>>>  
>>> @@ -37,4 +38,22 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
>>>  int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
>>>  				 int gamma_size);
>>>  
>>> +enum drm_color_encoding {
>>> +	DRM_COLOR_YCBCR_BT601,
>>> +	DRM_COLOR_YCBCR_BT709,
>>> +	DRM_COLOR_YCBCR_BT2020,
>>> +	DRM_COLOR_ENCODING_MAX,
>>> +};
>>> +
>>> +enum drm_color_range {
>>> +	DRM_COLOR_YCBCR_LIMITED_RANGE,
>>> +	DRM_COLOR_YCBCR_FULL_RANGE,
>>> +	DRM_COLOR_RANGE_MAX,
>>> +};
>>> +
>>> +int drm_plane_create_color_properties(struct drm_plane *plane,
>>> +				      u32 supported_encodings,
>>> +				      u32 supported_ranges,
>>> +				      enum drm_color_encoding default_encoding,
>>> +				      enum drm_color_range default_range);
>>>  #endif
>>> diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
>>> index 9ab3e70..f4de5f9 100644
>>> --- a/include/drm/drm_plane.h
>>> +++ b/include/drm/drm_plane.h
>>> @@ -26,6 +26,7 @@
>>>  #include <linux/list.h>
>>>  #include <linux/ctype.h>
>>>  #include <drm/drm_mode_object.h>
>>> +#include <drm/drm_color_mgmt.h>
>>>  
>>>  struct drm_crtc;
>>>  struct drm_printer;
>>> @@ -112,6 +113,10 @@ struct drm_plane_state {
>>>  	unsigned int zpos;
>>>  	unsigned int normalized_zpos;
>>>  
>>> +	/* Color encoding for non RGB formats */
>>> +	enum drm_color_encoding color_encoding;
>>> +	enum drm_color_range color_range;
>>> +
>>>  	/* Clipped coordinates */
>>>  	struct drm_rect src, dst;
>>>  
>>> @@ -523,6 +528,9 @@ struct drm_plane {
>>>  
>>>  	struct drm_property *zpos_property;
>>>  	struct drm_property *rotation_property;
>>> +
>>> +	struct drm_property *color_encoding_property;
>>> +	struct drm_property *color_range_property;
>>>  };
>>>  
>>>  #define obj_to_plane(x) container_of(x, struct drm_plane, base)
>>> -- 
>>> 1.9.1
>>
> 


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