Re: [RFC PATCH v3 23/23] drm/vkms: Add tests for CTM handling

[Pekka Paalanen <ppaalanen@gmail.com>]

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On Wed, 8 Nov 2023 11:36:42 -0500
Harry Wentland <harry.wentland@amd.com> wrote:

> A whole slew of tests for CTM handling that greatly helped in
> debugging the CTM code. The extent of tests might seem a bit
> silly but they're fast and might someday help save someone
> else's day when debugging this.

To be honest, this looks pretty limited testing. I guess the more
exhaustive tests are in IGT though, would be nice to mention that in
the commit message.

There is not a single case for out of [0.0, 1.0] input nor output.

The offset part is always zero.

> Signed-off-by: Harry Wentland <harry.wentland@amd.com>
> ---
>  drivers/gpu/drm/vkms/tests/vkms_color_tests.c | 258 ++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_composer.c          |   2 +-
>  2 files changed, 259 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/vkms/tests/vkms_color_tests.c b/drivers/gpu/drm/vkms/tests/vkms_color_tests.c
> index ad4c2f72fd1e..3eaa2233afbb 100644
> --- a/drivers/gpu/drm/vkms/tests/vkms_color_tests.c
> +++ b/drivers/gpu/drm/vkms/tests/vkms_color_tests.c
> @@ -3,6 +3,7 @@
>  #include <kunit/test.h>
>  
>  #include <drm/drm_fixed.h>
> +#include <drm/drm_mode.h>
>  
>  #define TEST_LUT_SIZE 16
>  
> @@ -80,11 +81,268 @@ static void vkms_color_srgb_inv_srgb(struct kunit *test)
>  	}
>  }
>  
> +#define FIXPT_HALF        (DRM_FIXED_ONE >> 1)
> +#define FIXPT_QUARTER     (DRM_FIXED_ONE >> 2)
> +
> +const struct drm_color_ctm_3x4 test_matrix_3x4_50_desat = { {
> +	FIXPT_HALF, FIXPT_QUARTER, FIXPT_QUARTER, 0,
> +	FIXPT_QUARTER, FIXPT_HALF, FIXPT_QUARTER, 0,
> +	FIXPT_QUARTER, FIXPT_QUARTER, FIXPT_HALF, 0
> +} };
> +
> +static void vkms_color_ctm_3x4_50_desat(struct kunit *test)
> +{
> +	struct pixel_argb_s32 ref, out;
> +
> +	/* full white */
> +	ref.a = 0x0;
> +	ref.r = 0xffff;
> +	ref.g = 0xffff;
> +	ref.b = 0xffff;
> +
> +	memcpy(&out, &ref, sizeof(out));
> +	apply_3x4_matrix(&out, &test_matrix_3x4_50_desat);
> +
> +	KUNIT_EXPECT_MEMEQ(test, &ref, &out, sizeof(out));
> +
> +	/* full black */
> +	ref.a = 0x0;

This is transparent, btw.

> +	ref.r = 0x0;
> +	ref.g = 0x0;
> +	ref.b = 0x0;
> +
> +	memcpy(&out, &ref, sizeof(out));
> +	apply_3x4_matrix(&out, &test_matrix_3x4_50_desat);
> +
> +	KUNIT_EXPECT_MEMEQ(test, &ref, &out, sizeof(out));
> +
> +	/* 50% grey */
> +	ref.a = 0x0;
> +	ref.r = 0x8000;
> +	ref.g = 0x8000;
> +	ref.b = 0x8000;
> +
> +	memcpy(&out, &ref, sizeof(out));
> +	apply_3x4_matrix(&out, &test_matrix_3x4_50_desat);
> +
> +	KUNIT_EXPECT_MEMEQ(test, &ref, &out, sizeof(out));
> +
> +	/* full red to 50% desat */
> +	ref.a = 0x0;
> +	ref.r = 0x7fff;
> +	ref.g = 0x3fff;
> +	ref.b = 0x3fff;
> +
> +	out.a = 0x0;
> +	out.r = 0xffff;
> +	out.g = 0x0;
> +	out.b = 0x0;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_50_desat);
> +
> +	KUNIT_EXPECT_MEMEQ(test, &ref, &out, sizeof(out));
> +}
> +
> +const struct drm_color_ctm_3x4 test_matrix_3x4_bt709_enc = { {
> +	0x00000000366cf400ull, 0x00000000b7175900ull, 0x0000000127bb300ull, 0,
> +	0x800000001993b3a0ull, 0x800000005609fe80ull, 0x000000006f9db200ull, 0,
> +	0x000000009d70a400ull, 0x800000008f011100ull, 0x800000000e6f9330ull, 0
> +} };

Would be nice to have a comment explaining where these values came
from, like a snippet of Python printing these. The conversion from real
numbers to this representation is the interesting part.

> +
> +static void vkms_color_ctm_3x4_bt709(struct kunit *test)
> +{
> +	struct pixel_argb_s32 ref, out;
> +
> +	/* full white to bt709 */
> +	ref.a = 0x0;
> +	ref.r = 0xfffe; /* off by one in 16bpc not a big deal */
> +	ref.g = 0x0;
> +	ref.b = 0x0;
> +
> +	out.a = 0x0;
> +	out.r = 0xffff;
> +	out.g = 0xffff;
> +	out.b = 0xffff;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 255 */
> +	KUNIT_EXPECT_GT(test, out.r, 0xfe00);

This allows result grossly greater than 1.0.

> +
> +	/* green 0 */
> +	KUNIT_EXPECT_LT(test, out.g, 0x0100);

This allows grossly negative results.

> +
> +	/* blue 0 */
> +	KUNIT_EXPECT_LT(test, out.b, 0x0100);
> +
> +	/* full black to bt709 */
> +	ref.a = 0x0;
> +	ref.r = 0x0; /* off by one in 16bpc not a big deal */
> +	ref.g = 0x0;
> +	ref.b = 0x0;
> +
> +	out.a = 0x0;
> +	out.r = 0x0;
> +	out.g = 0x0;
> +	out.b = 0x0;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 0 */
> +	KUNIT_EXPECT_LT(test, out.r, 0x100);
> +
> +	/* green 0 */
> +	KUNIT_EXPECT_LT(test, out.g, 0x0100);
> +
> +	/* blue 0 */
> +	KUNIT_EXPECT_LT(test, out.b, 0x0100);
> +
> +	/* gray to bt709 */
> +	ref.a = 0x0;
> +	ref.r = 0x7fff; /* off by one in 16bpc not a big deal */
> +	ref.g = 0x0;
> +	ref.b = 0x0;

This ref does not seem to be used?

> +
> +	out.a = 0x0;
> +	out.r = 0x7fff;
> +	out.g = 0x7fff;
> +	out.b = 0x7fff;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 127 */
> +	KUNIT_EXPECT_GT(test, out.r, 0x7e00);
> +	KUNIT_EXPECT_LT(test, out.r, 0x8000);

Maybe a new macro for "expect in between", or "expect with +/-
tolerance"?


Thanks,
pq

> +
> +	/* green 0 */
> +	KUNIT_EXPECT_LT(test, out.g, 0x0100);
> +
> +	/* blue 0 */
> +	KUNIT_EXPECT_LT(test, out.b, 0x0100);
> +
> +	/* == red 255 - bt709 enc == */
> +	out.a = 0x0;
> +	out.r = 0xffff;
> +	out.g = 0x0;
> +	out.b = 0x0;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 54 */
> +	KUNIT_EXPECT_GT(test, out.r, 0x3500);
> +	KUNIT_EXPECT_LT(test, out.r, 0x3700);
> +
> +	/* green 0 */
> +	KUNIT_EXPECT_LT(test, out.g, 0x0100);
> +
> +	/* blue 157 */
> +	KUNIT_EXPECT_GT(test, out.b, 0x9C00);
> +	KUNIT_EXPECT_LT(test, out.b, 0x9E00);
> +
> +
> +	/* == green 255 - bt709 enc == */
> +	out.a = 0x0;
> +	out.r = 0x0;
> +	out.g = 0xffff;
> +	out.b = 0x0;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 182 */
> +	KUNIT_EXPECT_GT(test, out.r, 0xB500);
> +	KUNIT_EXPECT_LT(test, out.r, 0xB780); /* laxed by half*/
> +
> +	/* green 0 */
> +	KUNIT_EXPECT_LT(test, out.g, 0x0100);
> +
> +	/* blue 0 */
> +	KUNIT_EXPECT_LT(test, out.b, 0x0100);
> +
> +	/* == blue 255 - bt709 enc == */
> +	out.a = 0x0;
> +	out.r = 0x0;
> +	out.g = 0x0;
> +	out.b = 0xffff;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 18 */
> +	KUNIT_EXPECT_GT(test, out.r, 0x1100);
> +	KUNIT_EXPECT_LT(test, out.r, 0x1300);
> +
> +	/* green 111 */
> +	KUNIT_EXPECT_GT(test, out.g, 0x6E00);
> +	KUNIT_EXPECT_LT(test, out.g, 0x7000);
> +
> +	/* blue 0 */
> +	KUNIT_EXPECT_LT(test, out.b, 0x0100);
> +
> +	/* == red 140 - bt709 enc == */
> +	out.a = 0x0;
> +	out.r = 0x8c8c;
> +	out.g = 0x0;
> +	out.b = 0x0;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 30 */
> +	KUNIT_EXPECT_GT(test, out.r, 0x1D00);
> +	KUNIT_EXPECT_LT(test, out.r, 0x1F00);
> +
> +	/* green 0 */
> +	KUNIT_EXPECT_LT(test, out.g, 0x100);
> +
> +	/* blue 87 */
> +	KUNIT_EXPECT_GT(test, out.b, 0x5600);
> +	KUNIT_EXPECT_LT(test, out.b, 0x5800);
> +
> +	/* == green 140 - bt709 enc == */
> +	out.a = 0x0;
> +	out.r = 0x0;
> +	out.g = 0x8c8c;
> +	out.b = 0x0;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 30 */
> +	KUNIT_EXPECT_GT(test, out.r, 0x6400);
> +	KUNIT_EXPECT_LT(test, out.r, 0x6600);
> +
> +	/* green 0 */
> +	KUNIT_EXPECT_LT(test, out.g, 0x100);
> +
> +	/* blue 0 */
> +	KUNIT_EXPECT_LT(test, out.b, 0x100);
> +
> +
> +	/* == blue 140 - bt709 enc == */
> +	out.a = 0x0;
> +	out.r = 0x0;
> +	out.g = 0x0;
> +	out.b = 0x8c8c;
> +
> +	apply_3x4_matrix(&out, &test_matrix_3x4_bt709_enc);
> +
> +	/* red 30 */
> +	KUNIT_EXPECT_GT(test, out.r, 0x900);
> +	KUNIT_EXPECT_LT(test, out.r, 0xB00);
> +
> +	/* green 61 */
> +	KUNIT_EXPECT_GT(test, out.g, 0x3C00);
> +	KUNIT_EXPECT_LT(test, out.g, 0x3E00);
> +
> +	/* blue 0 */
> +	KUNIT_EXPECT_LT(test, out.b, 0x100);
> +
> +}
> +
>  static struct kunit_case vkms_color_test_cases[] = {
>  	KUNIT_CASE(vkms_color_test_get_lut_index),
>  	KUNIT_CASE(vkms_color_test_lerp),
>  	KUNIT_CASE(vkms_color_test_linear),
>  	KUNIT_CASE(vkms_color_srgb_inv_srgb),
> +	KUNIT_CASE(vkms_color_ctm_3x4_50_desat),
> +	KUNIT_CASE(vkms_color_ctm_3x4_bt709),
>  	{}
>  };
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> index c278fb223188..4ead5346007a 100644
> --- a/drivers/gpu/drm/vkms/vkms_composer.c
> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> @@ -164,7 +164,7 @@ static void apply_lut(const struct vkms_crtc_state *crtc_state, struct line_buff
>  	}
>  }
>  
> -static void apply_3x4_matrix(struct pixel_argb_s32 *pixel, const struct drm_color_ctm_3x4 *matrix)
> +void apply_3x4_matrix(struct pixel_argb_s32 *pixel, const struct drm_color_ctm_3x4 *matrix)
>  {
>  	s64 rf, gf, bf;
>  


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