Hi

Am 22.09.22 um 16:25 schrieb Maxime Ripard:
> drm_connector_pick_cmdline_mode() is in charge of finding a proper
> drm_display_mode from the definition we got in the video= command line
> argument.
> 
> Let's add some unit tests to make sure we're not getting any regressions
> there.
> 
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> 
> diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
> index bbc535cc50dd..d553e793e673 100644
> --- a/drivers/gpu/drm/drm_client_modeset.c
> +++ b/drivers/gpu/drm/drm_client_modeset.c
> @@ -1237,3 +1237,7 @@ int drm_client_modeset_dpms(struct drm_client_dev *client, int mode)
>   	return ret;
>   }
>   EXPORT_SYMBOL(drm_client_modeset_dpms);
> +
> +#ifdef CONFIG_DRM_KUNIT_TEST
> +#include "tests/drm_client_modeset_test.c"
> +#endif

I strongly dislike this style of including source files in each other. 
It's a recipe for all kind of build errors. Can you do something else?

As the tested function is an internal interface, maybe export a wrapper 
if tests are enabled, like this:

#ifdef CONFIG_DRM_KUNIT_TEST
struct drm_display_mode *
drm_connector_pick_cmdline_mode_kunit(drm_conenctor)
{
   return drm_connector_pick_cmdline_mode(connector)
}
EXPORT_SYMBOL(drm_connector_pick_cmdline_mode_kunit)
#endif

The wrapper's declaration can be located in the kunit test file.

Best regards
Thomas

> diff --git a/drivers/gpu/drm/tests/drm_client_modeset_test.c b/drivers/gpu/drm/tests/drm_client_modeset_test.c
> new file mode 100644
> index 000000000000..46335de7bc6b
> --- /dev/null
> +++ b/drivers/gpu/drm/tests/drm_client_modeset_test.c
> @@ -0,0 +1,114 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022 Maxime Ripard <mripard@kernel.org>
> + */
> +
> +#include <kunit/test.h>
> +
> +#include <drm/drm_connector.h>
> +#include <drm/drm_edid.h>
> +#include <drm/drm_drv.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_modeset_helper_vtables.h>
> +#include <drm/drm_probe_helper.h>
> +
> +#include "drm_kunit_helpers.h"
> +
> +struct drm_client_modeset_test_priv {
> +	struct drm_device *drm;
> +	struct drm_connector connector;
> +};
> +
> +static int drm_client_modeset_connector_get_modes(struct drm_connector *connector)
> +{
> +	struct drm_display_mode *mode;
> +	int count;
> +
> +	count = drm_add_modes_noedid(connector, 1920, 1200);
> +
> +	return count;
> +}
> +
> +static const struct drm_connector_helper_funcs drm_client_modeset_connector_helper_funcs = {
> +	.get_modes = drm_client_modeset_connector_get_modes,
> +};
> +
> +static const struct drm_connector_funcs drm_client_modeset_connector_funcs = {
> +};
> +
> +static int drm_client_modeset_test_init(struct kunit *test)
> +{
> +	struct drm_client_modeset_test_priv *priv;
> +	int ret;
> +
> +	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +	test->priv = priv;
> +
> +	priv->drm = drm_kunit_device_init("drm-client-modeset-test");
> +	if (IS_ERR(priv->drm))
> +		return PTR_ERR(priv->drm);
> +
> +	ret = drmm_connector_init(priv->drm, &priv->connector,
> +				  &drm_client_modeset_connector_funcs,
> +				  DRM_MODE_CONNECTOR_Unknown,
> +				  NULL);
> +	if (ret)
> +		return ret;
> +	drm_connector_helper_add(&priv->connector, &drm_client_modeset_connector_helper_funcs);
> +
> +	return 0;
> +}
> +
> +static void drm_client_modeset_test_exit(struct kunit *test)
> +{
> +	struct drm_client_modeset_test_priv *priv = test->priv;
> +
> +	drm_kunit_device_exit(priv->drm);
> +}
> +
> +static void drm_pick_cmdline_res_1920_1080_60(struct kunit *test)
> +{
> +	struct drm_client_modeset_test_priv *priv = test->priv;
> +	struct drm_device *drm = priv->drm;
> +	struct drm_connector *connector = &priv->connector;
> +	struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;
> +	struct drm_display_mode *expected_mode, *mode;
> +	const char *cmdline = "1920x1080@60";
> +	int ret;
> +
> +	expected_mode = drm_mode_find_dmt(priv->drm, 1920, 1080, 60, false);
> +	KUNIT_ASSERT_PTR_NE(test, expected_mode, NULL);
> +
> +	KUNIT_ASSERT_TRUE(test,
> +			  drm_mode_parse_command_line_for_connector(cmdline,
> +								    connector,
> +								    cmdline_mode));
> +
> +	mutex_lock(&drm->mode_config.mutex);
> +	ret = drm_helper_probe_single_connector_modes(connector, 1920, 1080);
> +	mutex_unlock(&drm->mode_config.mutex);
> +	KUNIT_ASSERT_GT(test, ret, 0);
> +
> +	mode = drm_connector_pick_cmdline_mode(connector);
> +	KUNIT_ASSERT_PTR_NE(test, mode, NULL);
> +
> +	KUNIT_EXPECT_TRUE(test, drm_mode_equal(expected_mode, mode));
> +}
> +
> +static struct kunit_case drm_pick_cmdline_tests[] = {
> +	KUNIT_CASE(drm_pick_cmdline_res_1920_1080_60),
> +	{}
> +};
> +
> +static struct kunit_suite drm_pick_cmdline_test_suite = {
> +	.name = "drm_pick_cmdline",
> +	.init = drm_client_modeset_test_init,
> +	.exit = drm_client_modeset_test_exit,
> +	.test_cases = drm_pick_cmdline_tests
> +};
> +
> +kunit_test_suite(drm_pick_cmdline_test_suite);
> +MODULE_AUTHOR("Maxime Ripard <mripard@kernel.org>");
> +MODULE_LICENSE("GPL");
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev