[PATCH v16 5/7] drm/vkms: Create KUnit tests for YUV conversions

Louis Chauvet
2025-01-21T10:48:19Z

From: Arthur Grillo <arthurgrillo@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@riseup.net>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
drivers/gpu/drm/vkms/Kconfig | 15 ++
drivers/gpu/drm/vkms/Makefile | 1 +
drivers/gpu/drm/vkms/tests/.kunitconfig | 4 +
drivers/gpu/drm/vkms/tests/Makefile | 3 +
drivers/gpu/drm/vkms/tests/vkms_format_test.c | 271 ++++++++++++++++++++++++++
drivers/gpu/drm/vkms/vkms_formats.c | 7 +-
drivers/gpu/drm/vkms/vkms_formats.h | 5 +
7 files changed, 304 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/Kconfig b/drivers/gpu/drm/vkms/Kconfig
index 9def079f685bd30e1df3e4082e4818e402395391..d4665e913de7702fbd5c0f047876dad9715c690a 100644
--- a/drivers/gpu/drm/vkms/Kconfig
+++ b/drivers/gpu/drm/vkms/Kconfig
@@ -14,3 +14,18 @@ config DRM_VKMS
a VKMS.

If M is selected the module will be called vkms.
+
+config DRM_VKMS_KUNIT_TESTS
+ tristate "KUnit tests for VKMS." if !KUNIT_ALL_TESTS
+ depends on DRM_VKMS && KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ This builds unit tests for VKMS. This option is not useful for
+ distributions or general kernels, but only for kernel
+ developers working on VKMS.
+
+ For more information on KUnit and unit tests in general,
+ please refer to the KUnit documentation in
+ Documentation/dev-tools/kunit/.
+
+ If in doubt, say "N".
diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile
index 1b28a6a32948b557867dda51d2ccfdea687a2b62..8d3e46dde6350558a0aab4254df0dfe863f9c6ce 100644
--- a/drivers/gpu/drm/vkms/Makefile
+++ b/drivers/gpu/drm/vkms/Makefile
@@ -9,3 +9,4 @@ vkms-y := \
vkms_writeback.o

obj-$(CONFIG_DRM_VKMS) += vkms.o
+obj-$(CONFIG_DRM_VKMS_KUNIT_TESTS) += tests/
diff --git a/drivers/gpu/drm/vkms/tests/.kunitconfig b/drivers/gpu/drm/vkms/tests/.kunitconfig
new file mode 100644
index 0000000000000000000000000000000000000000..70e378228cbdaa025f01641f207a93a6c01f0853
--- /dev/null
+++ b/drivers/gpu/drm/vkms/tests/.kunitconfig
@@ -0,0 +1,4 @@
+CONFIG_KUNIT=y
+CONFIG_DRM=y
+CONFIG_DRM_VKMS=y
+CONFIG_DRM_VKMS_KUNIT_TESTS=y
diff --git a/drivers/gpu/drm/vkms/tests/Makefile b/drivers/gpu/drm/vkms/tests/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..2d1df668569e4f243ed9a06c1e16e595c131c4f6
--- /dev/null
+++ b/drivers/gpu/drm/vkms/tests/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+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 0000000000000000000000000000000000000000..aa81347ddce2288933abc2ff5b79f0ee11ff4271
--- /dev/null
+++ b/drivers/gpu/drm/vkms/tests/vkms_format_test.c
@@ -0,0 +1,271 @@
+// 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 {
+ 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)
+ *
+ * Test cases for conversion between YUV BT601 full range and RGB
+ * 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)
+ * Test cases for conversion between YUV BT601 limited range and RGB
+ * 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)
+ * Test cases for conversion between YUV BT709 full range and RGB
+ * using the ITU-R BT.709 weights.
+ */
+ {
+ .encoding = DRM_COLOR_YCBCR_BT709,
+ .range = DRM_COLOR_YCBCR_FULL_RANGE,
+ .n_colors = 4,
+ .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)
+ * Test cases for conversion between YUV BT709 limited range and RGB
+ * using the ITU-R BT.709 weights.
+ */
+ {
+ .encoding = DRM_COLOR_YCBCR_BT709,
+ .range = DRM_COLOR_YCBCR_LIMITED_RANGE,
+ .n_colors = 4,
+ .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)
+ * Test cases for conversion between YUV BT2020 full range and RGB
+ * using the ITU-R BT.2020 weights.
+ */
+ {
+ .encoding = DRM_COLOR_YCBCR_BT2020,
+ .range = DRM_COLOR_YCBCR_FULL_RANGE,
+ .n_colors = 4,
+ .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)
+ * Test cases for conversion between YUV BT2020 limited range and RGB
+ * using the ITU-R BT.709 weights.
+ */
+ {
+ .encoding = DRM_COLOR_YCBCR_BT2020,
+ .range = DRM_COLOR_YCBCR_LIMITED_RANGE,
+ .n_colors = 4,
+ .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 1f3ce4f334be9560e62c9a7fd933fa0ed6640e8f..0b867444999105262c855a24bf03bc66d9ebea1b 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 d583855cb32027d16b73d2a5b5a0644b13191d08..b4fe62ab9c65d465925d29911f26612193a80799 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_ */

--
2.47.1