Re: [PATCH v2 1/4] drm/tests: helpers: Add helper for drm_display_mode_from_cea_vic()

[Jinjie Ruan <ruanjinjie@huawei.com>]

On 2024/10/16 17:35, Maxime Ripard wrote:
> On Mon, Oct 14, 2024 at 08:52:01PM GMT, Jinjie Ruan wrote:
>> As Maxime suggested, add a new helper
>> drm_kunit_helper_display_mode_from_cea_vic(), it can replace
>> the direct call of drm_display_mode_from_cea_vic(), and it will
>> help solving the `mode` memory leaks.
>>
>> Suggested-by: Maxime Ripard <mripard@kernel.org>
>> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
>> ---
>>  drivers/gpu/drm/tests/drm_kunit_helpers.c | 40 +++++++++++++++++++++++
>>  include/drm/drm_kunit_helpers.h           |  6 ++++
>>  2 files changed, 46 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/tests/drm_kunit_helpers.c b/drivers/gpu/drm/tests/drm_kunit_helpers.c
>> index aa62719dab0e..dc70bafcd394 100644
>> --- a/drivers/gpu/drm/tests/drm_kunit_helpers.c
>> +++ b/drivers/gpu/drm/tests/drm_kunit_helpers.c
>> @@ -311,6 +311,46 @@ drm_kunit_helper_create_crtc(struct kunit *test,
>>  }
>>  EXPORT_SYMBOL_GPL(drm_kunit_helper_create_crtc);
>>  
>> +static void kunit_action_drm_mode_destroy(void *ptr)
>> +{
>> +	struct drm_display_mode *mode = ptr;
>> +
>> +	drm_mode_destroy(NULL, mode);
>> +}
>> +
>> +/**
>> + * drm_kunit_helper_display_mode_from_cea_vic() - return a mode for CEA VIC
>> +						  for a KUnit test
>> + * @test: The test context object
>> + * @dev: DRM device
>> + * @video_code: CEA VIC of the mode
>> + *
>> + * Creates a new mode matching the specified CEA VIC for a KUnit test.
>> + *
>> + * Resources will be cleaned up automatically.
>> + *
>> + * Returns: A new drm_display_mode on success or NULL on failure
>> + */
>> +struct drm_display_mode *
>> +drm_kunit_helper_display_mode_from_cea_vic(struct kunit *test,
>> +					   struct drm_device *dev,
>> +					   u8 video_code)
>> +{
>> +	struct drm_display_mode *mode;
>> +	int ret;
>> +
>> +	mode = drm_display_mode_from_cea_vic(dev, video_code);
>> +
>> +	ret = kunit_add_action_or_reset(test,
>> +					kunit_action_drm_mode_destroy,
>> +					mode);
>> +	if (ret)
>> +		return NULL;
>> +
>> +	return mode;
>> +}
>> +EXPORT_SYMBOL_GPL(drm_kunit_helper_display_mode_from_cea_vic);
>> +
> 
> I think you can drop the "helper" name there, it's usually reserved for
> blanket implementation of DRM hooks. This one isn't a hook, so just
> calling it drm_kunit_display_mode_from_cea_vic makes a bit more sense to
> me.
> 
>>  MODULE_AUTHOR("Maxime Ripard <maxime@cerno.tech>");
>>  MODULE_DESCRIPTION("KUnit test suite helper functions");
>>  MODULE_LICENSE("GPL");
>> diff --git a/include/drm/drm_kunit_helpers.h b/include/drm/drm_kunit_helpers.h
>> index e7cc17ee4934..1e7fd4be550c 100644
>> --- a/include/drm/drm_kunit_helpers.h
>> +++ b/include/drm/drm_kunit_helpers.h
>> @@ -4,6 +4,7 @@
>>  #define DRM_KUNIT_HELPERS_H_
>>  
>>  #include <drm/drm_drv.h>
>> +#include <drm/drm_edid.h>
>>
>>  #include <linux/device.h>
>>  
>> @@ -120,4 +121,9 @@ drm_kunit_helper_create_crtc(struct kunit *test,
>>  			     const struct drm_crtc_funcs *funcs,
>>  			     const struct drm_crtc_helper_funcs *helper_funcs);
>>  
>> +struct drm_display_mode *
>> +drm_kunit_helper_display_mode_from_cea_vic(struct kunit *test,
>> +					   struct drm_device *dev,
>> +					   u8 video_code);
> 
> It's not clear to me what you need the drm_edid header, you just return
> a drm_display_mode pointer so you can just forward declare the structure


There is a compile error without the header，because there is no
"drm_display_mode_from_cea_vic()" declare.

drivers/gpu/drm/tests/drm_kunit_helpers.c:341:16: error: implicit
declaration of function ‘drm_display_mode_from_cea_vic’; did you mean
‘drm_kunit_display_mode_from_cea_vic’?
[-Werror=implicit-function-declaration]
  341 |         mode = drm_display_mode_from_cea_vic(dev, video_code);
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                drm_kunit_display_mode_from_cea_vic
drivers/gpu/drm/tests/drm_kunit_helpers.c:341:14: warning: assignment to
‘struct drm_display_mode *’ from ‘int’ makes pointer from integer
without a cast [-Wint-conversion]
  341 |         mode = drm_display_mode_from_cea_vic(dev, video_code);
      |              ^


> 
> Once fixed
> Acked-by: Maxime Ripard <mripard@kernel.org>
> 
> Maxime