[RFC PATCH 1/1] drm/format-helper: Add KUnit tests for drm_fb_xrgb8888_to_rgb332()

[Javier Martinez Canillas]

Hello José,

On 5/30/22 12:20, José Expósito wrote:
> Test the conversion from XRGB8888 to RGB332.
> 
> What is tested?
> 
>  - Different values for the X in XRGB8888 to make sure it is ignored
>  - Different clip values: Single pixel and full and partial buffer
>  - Well know colors: White, black, red, green, blue, magenta, yellow
>    and cyan
>  - Other colors: Randomly picked
>  - Destination pitch
> 
> Suggested-by: Javier Martinez Canillas <javierm at redhat.com>
> Signed-off-by: José Expósito <jose.exposito89 at gmail.com>
> ---

Thanks a lot for working on this! It's very cool to see the first KUnit
tests added to DRM :)

>  drivers/gpu/drm/Kconfig                  |  12 ++
>  drivers/gpu/drm/Makefile                 |   3 +
>  drivers/gpu/drm/drm_format_helper_test.c | 166 +++++++++++++++++++++++
>  3 files changed, 181 insertions(+)
>  create mode 100644 drivers/gpu/drm/drm_format_helper_test.c
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index e88c497fa010..d92be6faef15 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -76,6 +76,18 @@ config DRM_KMS_HELPER
>  	help
>  	  CRTC helpers for KMS drivers.
>  
> +config DRM_FORMAR_HELPER_TEST

I wonder if we want this level of detail for the test Kconfig symbols.
Maybe we could just have a DRM_KUNIT_TEST symbol that will enable all
the KUnit test suites for DRM ?

> +	bool "drm_format_helper tests" if !KUNIT_ALL_TESTS
> +	depends on DRM && KUNIT=y
> +	select DRM_KMS_HELPER

Daniel didn't like this `select DRM_KMS_HELPER` and I think that we can avoid
it if instead drm_format_helper_test.c is included in drm_format_helper.c, i.e:

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index a3ccd8bc966f..d63e02da528f 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -692,3 +692,7 @@ void drm_fb_xrgb8888_to_mono(void *dst, unsigned int dst_pitch, const void *vadd
        kfree(src32);
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono);
+
+#ifdef DRM_KUNIT_TEST
+#include "drm_format_helper_test.c"
+#endif

This also has the advantage that will allow to have KUnit tests for the static
functions that are only available in the drm_format_helper.c compilation unit.

>  obj-$(CONFIG_DRM_DEBUG_SELFTEST) += selftests/
> +obj-$(CONFIG_DRM_FORMAR_HELPER_TEST) += drm_kms_helper.o \
> +		drm_format_helper_test.o

And doing that will also allow you to get rid of this, since just selecting
CONFIG_DRM_KUNIT_TEST=y would be enough for the tests built and run by KUnit.

> +CFLAGS_drm_format_helper_test.o += $(DISABLE_STRUCTLEAK_PLUGIN)
>

A comment on why this is needed would useful.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat