[PATCH v18 6/8] drm/vkms: Create KUnit tests for YUV conversions

Louis Chauvet louis.chauvet at bootlin.com
Mon May 12 13:07:55 UTC 2025


Hi Maxime,

Did you have the time to look at this patch?

Pekka added his Acked-by, but as you made some remarks about this patch, 
I would like to have your validation before applying it.

Thanks a lot,
Louis Chauvet

Le 15/04/2025 à 15:55, Louis Chauvet a écrit :
> From: Arthur Grillo <arthurgrillo at riseup.net>
> 
> Create KUnit tests to test the conversion between YUV and RGB. Test each
> conversion and range combination with some common colors.
> 
> The code used to compute the expected result can be found in comment.
> 
> [Louis Chauvet:
> - fix minor formating issues (whitespace, double line)
> - change expected alpha from 0x0000 to 0xffff
> - adapt to the new get_conversion_matrix usage
> - apply the changes from Arthur
> - move struct pixel_yuv_u8 to the test itself]
> 
> Signed-off-by: Arthur Grillo <arthurgrillo at riseup.net>
> Acked-by: Pekka Paalanen <pekka.paalanen at collabora.com>
> Signed-off-by: Louis Chauvet <louis.chauvet at bootlin.com>
> ---
>   drivers/gpu/drm/vkms/tests/Makefile           |   1 +
>   drivers/gpu/drm/vkms/tests/vkms_format_test.c | 280 ++++++++++++++++++++++++++
>   drivers/gpu/drm/vkms/vkms_formats.c           |   7 +-
>   drivers/gpu/drm/vkms/vkms_formats.h           |   5 +
>   4 files changed, 291 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/tests/Makefile b/drivers/gpu/drm/vkms/tests/Makefile
> index 9ded37b67a46..0ee077942ae2 100644
> --- a/drivers/gpu/drm/vkms/tests/Makefile
> +++ b/drivers/gpu/drm/vkms/tests/Makefile
> @@ -1,3 +1,4 @@
>   # SPDX-License-Identifier: GPL-2.0-only
>   
>   obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += vkms_config_test.o
> +obj-$(CONFIG_DRM_VKMS_KUNIT_TESTS) += vkms_format_test.o
> diff --git a/drivers/gpu/drm/vkms/tests/vkms_format_test.c b/drivers/gpu/drm/vkms/tests/vkms_format_test.c
> new file mode 100644
> index 000000000000..2e1daef94831
> --- /dev/null
> +++ b/drivers/gpu/drm/vkms/tests/vkms_format_test.c
> @@ -0,0 +1,280 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +#include <kunit/test.h>
> +
> +#include <drm/drm_fixed.h>
> +#include <drm/drm_fourcc.h>
> +
> +#include "../../drm_crtc_internal.h"
> +
> +#include "../vkms_formats.h"
> +
> +#define TEST_BUFF_SIZE 50
> +
> +MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
> +
> +/**
> + * struct pixel_yuv_u8 - Internal representation of a pixel color.
> + * @y: Luma value, stored in 8 bits, without padding, using
> + *     machine endianness
> + * @u: Blue difference chroma value, stored in 8 bits, without padding, using
> + *     machine endianness
> + * @v: Red difference chroma value, stored in 8 bits, without padding, using
> + *     machine endianness
> + */
> +struct pixel_yuv_u8 {
> +	u8 y, u, v;
> +};
> +
> +/*
> + * struct yuv_u8_to_argb_u16_case - Reference values to test the color
> + * conversions in VKMS between YUV to ARGB
> + *
> + * @encoding: Encoding used to convert RGB to YUV
> + * @range: Range used to convert RGB to YUV
> + * @n_colors: Count of test colors in this case
> + * @format_pair.name: Name used for this color conversion, used to
> + *                    clarify the test results
> + * @format_pair.rgb: RGB color tested
> + * @format_pair.yuv: Same color as @format_pair.rgb, but converted to
> + *                   YUV using @encoding and @range.
> + */
> +struct yuv_u8_to_argb_u16_case {
> +	enum drm_color_encoding encoding;
> +	enum drm_color_range range;
> +	size_t n_colors;
> +	struct format_pair {
> +		char *name;
> +		struct pixel_yuv_u8 yuv;
> +		struct pixel_argb_u16 argb;
> +	} colors[TEST_BUFF_SIZE];
> +};
> +
> +/*
> + * The YUV color representation were acquired via the colour python framework.
> + * Below are the function calls used for generating each case.
> + *
> + * For more information got to the docs:
> + * https://colour.readthedocs.io/en/master/generated/colour.RGB_to_YCbCr.html
> + */
> +static struct yuv_u8_to_argb_u16_case yuv_u8_to_argb_u16_cases[] = {
> +	/*
> +	 * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
> +	 *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.601"],
> +	 *                     in_bits = 16,
> +	 *                     in_legal = False,
> +	 *                     in_int = True,
> +	 *                     out_bits = 8,
> +	 *                     out_legal = False,
> +	 *                     out_int = True)
> +	 *
> +	 * Tests cases for color conversion generated by converting RGB
> +	 * values to YUV BT601 full range using the ITU-R BT.601 weights.
> +	 */
> +	{
> +		.encoding = DRM_COLOR_YCBCR_BT601,
> +		.range = DRM_COLOR_YCBCR_FULL_RANGE,
> +		.n_colors = 6,
> +		.colors = {
> +			{ "white", { 0xff, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
> +			{ "gray",  { 0x80, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
> +			{ "black", { 0x00, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
> +			{ "red",   { 0x4c, 0x55, 0xff }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
> +			{ "green", { 0x96, 0x2c, 0x15 }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
> +			{ "blue",  { 0x1d, 0xff, 0x6b }, { 0xffff, 0x0000, 0x0000, 0xffff }},
> +		},
> +	},
> +	/*
> +	 * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
> +	 *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.601"],
> +	 *                     in_bits = 16,
> +	 *                     in_legal = False,
> +	 *                     in_int = True,
> +	 *                     out_bits = 8,
> +	 *                     out_legal = True,
> +	 *                     out_int = True)
> +	 * Tests cases for color conversion generated by converting RGB
> +	 * values to YUV BT601 limited range using the ITU-R BT.601 weights.
> +	 */
> +	{
> +		.encoding = DRM_COLOR_YCBCR_BT601,
> +		.range = DRM_COLOR_YCBCR_LIMITED_RANGE,
> +		.n_colors = 6,
> +		.colors = {
> +			{ "white", { 0xeb, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
> +			{ "gray",  { 0x7e, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
> +			{ "black", { 0x10, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
> +			{ "red",   { 0x51, 0x5a, 0xf0 }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
> +			{ "green", { 0x91, 0x36, 0x22 }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
> +			{ "blue",  { 0x29, 0xf0, 0x6e }, { 0xffff, 0x0000, 0x0000, 0xffff }},
> +		},
> +	},
> +	/*
> +	 * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
> +	 *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.709"],
> +	 *                     in_bits = 16,
> +	 *                     in_legal = False,
> +	 *                     in_int = True,
> +	 *                     out_bits = 8,
> +	 *                     out_legal = False,
> +	 *                     out_int = True)
> +	 * Tests cases for color conversion generated by converting RGB
> +	 * values to YUV BT709 full range using the ITU-R BT.709 weights.
> +	 */
> +	{
> +		.encoding = DRM_COLOR_YCBCR_BT709,
> +		.range = DRM_COLOR_YCBCR_FULL_RANGE,
> +		.n_colors = 6,
> +		.colors = {
> +			{ "white", { 0xff, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
> +			{ "gray",  { 0x80, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
> +			{ "black", { 0x00, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
> +			{ "red",   { 0x36, 0x63, 0xff }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
> +			{ "green", { 0xb6, 0x1e, 0x0c }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
> +			{ "blue",  { 0x12, 0xff, 0x74 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
> +		},
> +	},
> +	/*
> +	 * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
> +	 *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.709"],
> +	 *                     in_bits = 16,
> +	 *                     int_legal = False,
> +	 *                     in_int = True,
> +	 *                     out_bits = 8,
> +	 *                     out_legal = True,
> +	 *                     out_int = True)
> +	 * Tests cases for color conversion generated by converting RGB
> +	 * values to YUV BT709 limited range using the ITU-R BT.709 weights.
> +	 */
> +	{
> +		.encoding = DRM_COLOR_YCBCR_BT709,
> +		.range = DRM_COLOR_YCBCR_LIMITED_RANGE,
> +		.n_colors = 6,
> +		.colors = {
> +			{ "white", { 0xeb, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
> +			{ "gray",  { 0x7e, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
> +			{ "black", { 0x10, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
> +			{ "red",   { 0x3f, 0x66, 0xf0 }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
> +			{ "green", { 0xad, 0x2a, 0x1a }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
> +			{ "blue",  { 0x20, 0xf0, 0x76 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
> +		},
> +	},
> +	/*
> +	 * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
> +	 *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.2020"],
> +	 *                     in_bits = 16,
> +	 *                     in_legal = False,
> +	 *                     in_int = True,
> +	 *                     out_bits = 8,
> +	 *                     out_legal = False,
> +	 *                     out_int = True)
> +	 * Tests cases for color conversion generated by converting RGB
> +	 * values to YUV BT2020 full range using the ITU-R BT.2020 weights.
> +	 */
> +	{
> +		.encoding = DRM_COLOR_YCBCR_BT2020,
> +		.range = DRM_COLOR_YCBCR_FULL_RANGE,
> +		.n_colors = 6,
> +		.colors = {
> +			{ "white", { 0xff, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
> +			{ "gray",  { 0x80, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
> +			{ "black", { 0x00, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
> +			{ "red",   { 0x43, 0x5c, 0xff }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
> +			{ "green", { 0xad, 0x24, 0x0b }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
> +			{ "blue",  { 0x0f, 0xff, 0x76 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
> +		},
> +	},
> +	/*
> +	 * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
> +	 *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.2020"],
> +	 *                     in_bits = 16,
> +	 *                     in_legal = False,
> +	 *                     in_int = True,
> +	 *                     out_bits = 8,
> +	 *                     out_legal = True,
> +	 *                     out_int = True)
> +	 * Tests cases for color conversion generated by converting RGB
> +	 * values to YUV BT2020 limited range using the ITU-R BT.2020 weights.
> +	 */
> +	{
> +		.encoding = DRM_COLOR_YCBCR_BT2020,
> +		.range = DRM_COLOR_YCBCR_LIMITED_RANGE,
> +		.n_colors = 6,
> +		.colors = {
> +			{ "white", { 0xeb, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
> +			{ "gray",  { 0x7e, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
> +			{ "black", { 0x10, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
> +			{ "red",   { 0x4a, 0x61, 0xf0 }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
> +			{ "green", { 0xa4, 0x2f, 0x19 }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
> +			{ "blue",  { 0x1d, 0xf0, 0x77 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
> +		},
> +	},
> +};
> +
> +/*
> + * vkms_format_test_yuv_u8_to_argb_u16 - Testing the conversion between YUV
> + * colors to ARGB colors in VKMS
> + *
> + * This test will use the functions get_conversion_matrix_to_argb_u16 and
> + * argb_u16_from_yuv888 to convert YUV colors (stored in
> + * yuv_u8_to_argb_u16_cases) into ARGB colors.
> + *
> + * The conversion between YUV and RGB is not totally reversible, so there may be
> + * some difference between the expected value and the result.
> + * In addition, there may be some rounding error as the input color is 8 bits
> + * and output color is 16 bits.
> + */
> +static void vkms_format_test_yuv_u8_to_argb_u16(struct kunit *test)
> +{
> +	const struct yuv_u8_to_argb_u16_case *param = test->param_value;
> +	struct pixel_argb_u16 argb;
> +
> +	for (size_t i = 0; i < param->n_colors; i++) {
> +		const struct format_pair *color = &param->colors[i];
> +		struct conversion_matrix matrix;
> +
> +		get_conversion_matrix_to_argb_u16
> +			(DRM_FORMAT_NV12, param->encoding, param->range, &matrix);
> +
> +		argb = argb_u16_from_yuv888(color->yuv.y, color->yuv.u, color->yuv.v, &matrix);
> +
> +		KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.a, color->argb.a), 0x1ff,
> +				    "On the A channel of the color %s expected 0x%04x, got 0x%04x",
> +				    color->name, color->argb.a, argb.a);
> +		KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.r, color->argb.r), 0x1ff,
> +				    "On the R channel of the color %s expected 0x%04x, got 0x%04x",
> +				    color->name, color->argb.r, argb.r);
> +		KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.g, color->argb.g), 0x1ff,
> +				    "On the G channel of the color %s expected 0x%04x, got 0x%04x",
> +				    color->name, color->argb.g, argb.g);
> +		KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.b, color->argb.b), 0x1ff,
> +				    "On the B channel of the color %s expected 0x%04x, got 0x%04x",
> +				    color->name, color->argb.b, argb.b);
> +	}
> +}
> +
> +static void vkms_format_test_yuv_u8_to_argb_u16_case_desc(struct yuv_u8_to_argb_u16_case *t,
> +							  char *desc)
> +{
> +	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "%s - %s",
> +		 drm_get_color_encoding_name(t->encoding), drm_get_color_range_name(t->range));
> +}
> +
> +KUNIT_ARRAY_PARAM(yuv_u8_to_argb_u16, yuv_u8_to_argb_u16_cases,
> +		  vkms_format_test_yuv_u8_to_argb_u16_case_desc
> +);
> +
> +static struct kunit_case vkms_format_test_cases[] = {
> +	KUNIT_CASE_PARAM(vkms_format_test_yuv_u8_to_argb_u16, yuv_u8_to_argb_u16_gen_params),
> +	{}
> +};
> +
> +static struct kunit_suite vkms_format_test_suite = {
> +	.name = "vkms-format",
> +	.test_cases = vkms_format_test_cases,
> +};
> +
> +kunit_test_suite(vkms_format_test_suite);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Kunit test for vkms format conversion");
> diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> index 8f7a5d54a076..9972780f3fa9 100644
> --- a/drivers/gpu/drm/vkms/vkms_formats.c
> +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> @@ -7,6 +7,8 @@
>   #include <drm/drm_rect.h>
>   #include <drm/drm_fixed.h>
>   
> +#include <kunit/visibility.h>
> +
>   #include "vkms_formats.h"
>   
>   /**
> @@ -247,8 +249,8 @@ static struct pixel_argb_u16 argb_u16_from_RGB565(const __le16 *pixel)
>   	return out_pixel;
>   }
>   
> -static struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel_2,
> -						  const struct conversion_matrix *matrix)
> +VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel_2,
> +							    const struct conversion_matrix *matrix)
>   {
>   	u16 r, g, b;
>   	s64 fp_y, fp_channel_1, fp_channel_2;
> @@ -278,6 +280,7 @@ static struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel
>   
>   	return argb_u16_from_u16161616(0xffff, r, g, b);
>   }
> +EXPORT_SYMBOL_IF_KUNIT(argb_u16_from_yuv888);
>   
>   /*
>    * The following functions are read_line function for each pixel format supported by VKMS.
> diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
> index d583855cb320..b4fe62ab9c65 100644
> --- a/drivers/gpu/drm/vkms/vkms_formats.h
> +++ b/drivers/gpu/drm/vkms/vkms_formats.h
> @@ -13,4 +13,9 @@ void get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encod
>   				       enum drm_color_range range,
>   				       struct conversion_matrix *matrix);
>   
> +#if IS_ENABLED(CONFIG_KUNIT)
> +struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel_2,
> +					   const struct conversion_matrix *matrix);
> +#endif
> +
>   #endif /* _VKMS_FORMATS_H_ */
> 

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com



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