Re: [V7 03/45] drm/vkms: Add kunit tests for VKMS LUT handling

[Louis Chauvet <louis.chauvet@bootlin.com>]

Le 20/12/2024 à 05:33, Alex Hung a écrit :
> From: Harry Wentland <harry.wentland@amd.com>
> 
> Debugging LUT math is much easier when we can unit test
> it. Add kunit functionality to VKMS and add tests for
>   - get_lut_index
>   - lerp_u16
> 
> Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
> Signed-off-by: Alex Hung <alex.hung@amd.com>
> Signed-off-by: Harry Wentland <harry.wentland@amd.com>
> Cc: Arthur Grillo <arthurgrillo@riseup.net>

Hi,

I would like to take this patch too. Can I take it with the 
modifications below:

> ---
> v7:
>   - Fix checkpatch warnings and errors (Louis Chauvet)
>    - Change SPDX-License-Identifier: GPL-2.0+ from /* */ to //
>    - Fix checkpatch errors and warnings (new line at EOF, redundant spaces, and long lines)
>    - Add static to const struct vkms_color_lut test_linear_lut
>   - Add "MODULE_DESCRIPTION" (Jeff Johnson)
> 
> v6:
>   - Eliminate need to include test as .c file (Louis Chauvet)
> 
> v5:
>   - Bring back static for lerp_u16 and get_lut_index (Arthur)
> 
> v4:
>   - Test the critical points of the lerp function (Pekka)
> 
> v3:
>   - Use include way of testing static functions (Arthur)
>   
>   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_color_test.c | 172 +++++++++++++++++++
>   drivers/gpu/drm/vkms/vkms_composer.c         |   8 +-
>   drivers/gpu/drm/vkms/vkms_composer.h         |  13 ++
>   7 files changed, 214 insertions(+), 2 deletions(-)
>   create mode 100644 drivers/gpu/drm/vkms/tests/.kunitconfig
>   create mode 100644 drivers/gpu/drm/vkms/tests/Makefile
>   create mode 100644 drivers/gpu/drm/vkms/tests/vkms_color_test.c
>   create mode 100644 drivers/gpu/drm/vkms/vkms_composer.h
> 
> diff --git a/drivers/gpu/drm/vkms/Kconfig b/drivers/gpu/drm/vkms/Kconfig
> index b9ecdebecb0b..59c4a32adb9d 100644
> --- a/drivers/gpu/drm/vkms/Kconfig
> +++ b/drivers/gpu/drm/vkms/Kconfig
> @@ -13,3 +13,18 @@ config DRM_VKMS
>   	  a VKMS.
>   
>   	  If M is selected the module will be called vkms.
> +
> +config DRM_VKMS_KUNIT_TESTS

Can I change to:

	config DRM_VKMS_KUNIT_TEST

> +	tristate "KUnit tests for VKMS." if !KUNIT_ALL_TESTS

Can I change to:

	tristate "KUnit tests for VKMS" if !KUNIT_ALL_TESTS

> +	depends on DRM_VKMS=y && KUNIT

Can I change to:

	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 1b28a6a32948..8d3e46dde635 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 000000000000..70e378228cbd
> --- /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 000000000000..7876ca7a3c42
> --- /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_color_test.o
> \ No newline at end of file
> diff --git a/drivers/gpu/drm/vkms/tests/vkms_color_test.c b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
> new file mode 100644
> index 000000000000..b53beaac2703
> --- /dev/null
> +++ b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
> @@ -0,0 +1,172 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +#include <kunit/test.h>
> +
> +#include <drm/drm_fixed.h>
> +#include <drm/drm_mode.h>
> +#include "../vkms_drv.h"
> +#include "../vkms_composer.h"
> +
> +#define TEST_LUT_SIZE 16
> +
> +MODULE_IMPORT_NS(EXPORTED_FOR_KUNIT_TESTING);

Needs to be changed to: (Can I do it?)

	MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");

Thanks,
Louis Chauvet

> +
> +static struct drm_color_lut test_linear_array[TEST_LUT_SIZE] = {
> +	{ 0x0, 0x0, 0x0, 0 },
> +	{ 0x1111, 0x1111, 0x1111, 0 },
> +	{ 0x2222, 0x2222, 0x2222, 0 },
> +	{ 0x3333, 0x3333, 0x3333, 0 },
> +	{ 0x4444, 0x4444, 0x4444, 0 },
> +	{ 0x5555, 0x5555, 0x5555, 0 },
> +	{ 0x6666, 0x6666, 0x6666, 0 },
> +	{ 0x7777, 0x7777, 0x7777, 0 },
> +	{ 0x8888, 0x8888, 0x8888, 0 },
> +	{ 0x9999, 0x9999, 0x9999, 0 },
> +	{ 0xaaaa, 0xaaaa, 0xaaaa, 0 },
> +	{ 0xbbbb, 0xbbbb, 0xbbbb, 0 },
> +	{ 0xcccc, 0xcccc, 0xcccc, 0 },
> +	{ 0xdddd, 0xdddd, 0xdddd, 0 },
> +	{ 0xeeee, 0xeeee, 0xeeee, 0 },
> +	{ 0xffff, 0xffff, 0xffff, 0 },
> +};
> +
> +static const struct vkms_color_lut test_linear_lut = {
> +	.base = test_linear_array,
> +	.lut_length = TEST_LUT_SIZE,
> +	.channel_value2index_ratio = 0xf000fll
> +};
> +
> +
> +static void vkms_color_test_get_lut_index(struct kunit *test)
> +{
> +	s64 lut_index;
> +	int i;
> +
> +	lut_index = get_lut_index(&test_linear_lut, test_linear_array[0].red);
> +	KUNIT_EXPECT_EQ(test, drm_fixp2int(lut_index), 0);
> +
> +	for (i = 0; i < TEST_LUT_SIZE; i++) {
> +		lut_index = get_lut_index(&test_linear_lut, test_linear_array[i].red);
> +		KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(lut_index), i);
> +	}
> +}
> +
> +static void vkms_color_test_lerp(struct kunit *test)
> +{
> +	/*** half-way round down ***/
> +	s64 t = 0x80000000 - 1;
> +
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x10, t), 0x8);
> +
> +	/* odd a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0x10, t), 0x8);
> +
> +	/* odd b */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0xf, t), 0x8);
> +
> +	/* b = a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x10, t), 0x10);
> +
> +	/* b = a + 1 */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x11, t), 0x10);
> +
> +	/*** half-way round up ***/
> +	t = 0x80000000;
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x10, t), 0x8);
> +
> +	/* odd a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0x10, t), 0x9);
> +
> +	/* odd b */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0xf, t), 0x8);
> +
> +	/* b = a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x10, t), 0x10);
> +
> +	/* b = a + 1 */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x11, t), 0x11);
> +
> +	/*** t = 0.0 ***/
> +	t = 0x0;
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x10, t), 0x0);
> +
> +	/* odd a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0x10, t), 0x1);
> +
> +	/* odd b */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0xf, t), 0x1);
> +
> +	/* b = a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x10, t), 0x10);
> +
> +	/* b = a + 1 */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x11, t), 0x10);
> +
> +	/*** t = 1.0 ***/
> +	t = 0x100000000;
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x10, t), 0x10);
> +
> +	/* odd a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0x10, t), 0x10);
> +
> +	/* odd b */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0xf, t), 0xf);
> +
> +	/* b = a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x10, t), 0x10);
> +
> +	/* b = a + 1 */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x11, t), 0x11);
> +
> +	/*** t = 0.0 + 1 ***/
> +	t = 0x0 + 1;
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x10, t), 0x0);
> +
> +	/* odd a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0x10, t), 0x1);
> +
> +	/* odd b */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0xf, t), 0x1);
> +
> +	/* b = a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x10, t), 0x10);
> +
> +	/* b = a + 1 */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x11, t), 0x10);
> +
> +	/*** t = 1.0 - 1 ***/
> +	t = 0x100000000 - 1;
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x10, t), 0x10);
> +
> +	/* odd a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0x10, t), 0x10);
> +
> +	/* odd b */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x1, 0xf, t), 0xf);
> +
> +	/* b = a */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x10, t), 0x10);
> +
> +	/* b = a + 1 */
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x10, 0x11, t), 0x11);
> +
> +	/*** t chosen to verify the flipping point of result a (or b) to a+1 (or b-1) ***/
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x1, 0x80000000 - 1), 0x0);
> +	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x1, 0x80000000), 0x1);
> +}
> +
> +static struct kunit_case vkms_color_test_cases[] = {
> +	KUNIT_CASE(vkms_color_test_get_lut_index),
> +	KUNIT_CASE(vkms_color_test_lerp),
> +	{}
> +};
> +
> +static struct kunit_suite vkms_color_test_suite = {
> +	.name = "vkms-color",
> +	.test_cases = vkms_color_test_cases,
> +};
> +
> +kunit_test_suite(vkms_color_test_suite);
> +
> +MODULE_DESCRIPTION("Kunit test for VKMS LUT handling");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> index 3d6785d081f2..d15ceac6c56f 100644
> --- a/drivers/gpu/drm/vkms/vkms_composer.c
> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> @@ -12,6 +12,8 @@
>   #include <linux/minmax.h>
>   
>   #include "vkms_drv.h"
> +#include <kunit/visibility.h>
> +#include "vkms_composer.h"
>   
>   static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha)
>   {
> @@ -91,7 +93,7 @@ static void fill_background(const struct pixel_argb_u16 *background_color,
>   }
>   
>   // lerp(a, b, t) = a + (b - a) * t
> -static u16 lerp_u16(u16 a, u16 b, s64 t)
> +VISIBLE_IF_KUNIT u16 lerp_u16(u16 a, u16 b, s64 t)
>   {
>   	s64 a_fp = drm_int2fixp(a);
>   	s64 b_fp = drm_int2fixp(b);
> @@ -100,13 +102,15 @@ static u16 lerp_u16(u16 a, u16 b, s64 t)
>   
>   	return drm_fixp2int_round(a_fp + delta);
>   }
> +EXPORT_SYMBOL_IF_KUNIT(lerp_u16);
>   
> -static s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value)
> +VISIBLE_IF_KUNIT s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value)
>   {
>   	s64 color_channel_fp = drm_int2fixp(channel_value);
>   
>   	return drm_fixp_mul(color_channel_fp, lut->channel_value2index_ratio);
>   }
> +EXPORT_SYMBOL_IF_KUNIT(get_lut_index);
>   
>   /*
>    * This enum is related to the positions of the variables inside
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.h b/drivers/gpu/drm/vkms/vkms_composer.h
> new file mode 100644
> index 000000000000..9316a053e7d7
> --- /dev/null
> +++ b/drivers/gpu/drm/vkms/vkms_composer.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +
> +#ifndef _VKMS_COMPOSER_H_
> +#define _VKMS_COMPOSER_H_
> +
> +#include <kunit/visibility.h>
> +
> +#if IS_ENABLED(CONFIG_KUNIT)
> +u16 lerp_u16(u16 a, u16 b, s64 t);
> +s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value);
> +#endif
> +
> +#endif /* _VKMS_COMPOSER_H_ */

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