Re: [PATCH v2] drm/i915/kunit: DP Link: Use if statements instead of for loops

On Wed, 12 Aug 2026, Jonathan Cavitt <[email protected]> wrote:
> The static functions get_target_config and get_fallback_config in
> intel_dp_link_test.c use for loops to determine if the requested index of
> the config set is in the bounds of the config set entry list.
>
> Reconfigure these functions to use if statements instead, as these for
> loops are only run for a single iteration.

The CI on intel-gfx doesn't run kunit tests, while intel-xe does.

Please send the changes to intel-xe, and double check that the link
tests get run, before merging.

> Issue caught by static analysis.
>
> v2: (Michal)
> - Change i <= 0 check to i == 0, as i cannot be negative by assertion
> - Remove unnecessary newlines
>
> Signed-off-by: Jonathan Cavitt <[email protected]>
> Cc: Imre Deak <[email protected]>
> Cc: Michal Grzelak <[email protected]>
> ---
>  .../i915/display/tests/intel_dp_link_test.c   | 34 ++++++++-----------
>  1 file changed, 15 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/tests/intel_dp_link_test.c b/drivers/gpu/drm/i915/display/tests/intel_dp_link_test.c
> index 67c6fe9f1812..6dfd8903a8ec 100644
> --- a/drivers/gpu/drm/i915/display/tests/intel_dp_link_test.c
> +++ b/drivers/gpu/drm/i915/display/tests/intel_dp_link_test.c
> @@ -1215,22 +1215,20 @@ static bool get_fallback_config(const struct test_config_table *expected_table,
>  	struct kunit *test = expected_table->test;
>  	const struct link_config_set *config_set =
>  		get_fallback_configs_for_output_type(test, output_type);
> +	const struct intel_dp_link_config *config;
>  	int i;
>  
>  	i = lookup_config(config_set, target_config);
>  	KUNIT_ASSERT_GE(test, i, 0);
>  
> -	for (i--; i >= 0; i--) {
> -		const struct intel_dp_link_config *config =
> -			&config_set->entries[i];
> +	if (!i)
> +		return false;
>  
> -		assert_config_is_supported(expected_table, config);
> -		*fallback_config = *config;
> +	config = &config_set->entries[i-1];

Nitpick, checkpatch should complain about missing spaces around the
operand in "i-1".

> +	assert_config_is_supported(expected_table, config);
> +	*fallback_config = *config;
>  
> -		return true;
> -	}
> -
> -	return false;
> +	return true;
>  }
>  
>  static bool get_target_config(const struct test_config_table *expected_table,
> @@ -1240,19 +1238,17 @@ static bool get_target_config(const struct test_config_table *expected_table,
>  	struct kunit *test = expected_table->test;
>  	const struct link_config_set *config_set =
>  		get_target_configs_for_output_type(test, output_type);
> -	int i;
> +	const struct intel_dp_link_config *config;
> +	int i = config_set->size - 1;
>  
> -	for (i = config_set->size - 1; i >= 0; i--) {
> -		const struct intel_dp_link_config *config =
> -			&config_set->entries[i];
> +	if (i < 0)
> +		return false;
>  
> -		assert_config_is_supported(expected_table, config);
> -		*target = *config;
> +	config = &config_set->entries[i];
> +	assert_config_is_supported(expected_table, config);
> +	*target = *config;
>  
> -		return true;
> -	}
> -
> -	return false;
> +	return true;
>  }
>  
>  static void test_fallback_seq(struct kunit *test,

-- 
Jani Nikula, Intel