Re: [PATCH i-g-t v9 05/49] lib/igt_kms: Add helper to wait for new connectors

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

On 3/17/26 15:56, Kory Maincent wrote:
> On Mon, 16 Mar 2026 17:17:26 +0100
> Louis Chauvet <louis.chauvet@bootlin.com> wrote:
> 
>> Add list comparison utilities and a new function to wait for new
>> connectors to appear on the system.
>>
>> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
>> Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
>> ---
>>   lib/igt_kms.c | 97
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ lib/igt_kms.h |
>> 6 ++++ 2 files changed, 103 insertions(+)
>>
>> diff --git a/lib/igt_kms.c b/lib/igt_kms.c
>> index f0f27ccda9d8..b220de419a70 100644
>> --- a/lib/igt_kms.c
>> +++ b/lib/igt_kms.c
>> @@ -8322,3 +8322,100 @@ uint32_t igt_get_connector_id_from_mst_path(int
>> drm_fd, const void *mst_path)
>>   	return 0;
>>   }
>> +
>> +/**
>> + * array_contains() - Search an element in the array
>> + *
>> + * @array: Pointer to the array to search into
>> + * @array_len: Length of the array
>> + * @value: Value to search in the array
>> + *
>> + * Returns true if @array contains @value
>> + */
>> +static bool array_contains(const uint32_t *array, int array_len, uint32_t
>> value) +{
>> +	igt_assert(array_len == 0 || array);
>> +
>> +	for (int i = 0; i < array_len; i++)
>> +		if (array[i] == value)
>> +			return true;
>> +
>> +	return false;
>> +}
>> +
>> +/**
>> + * get_array_diff() - Compute and return the set difference between two
>> arrays
>> + *
>> + * @array_a: Pointer to the first array to compare
>> + * @array_a_len: Length of the first array
>> + * @array_b: Pointer to the second array to compare
>> + * @array_b_len: Length of the second array
>> + * @diff: Out pointer returning a array of items in @array_a but not
>> + *        in @array_b. Can be NULL to only count the elements.
>> + *
>> + * Returns the number of element which are in @array_a but not in @array_b.
>> + */
>> +int
>> +get_array_diff(const uint32_t *array_a, int array_a_len, const uint32_t
>> *array_b, int array_b_len,
>> +	       uint32_t **diff)
>> +{
>> +	int diff_len = 0;
>> +
>> +	igt_assert(array_a_len == 0 || array_a);
>> +	igt_assert(array_b_len == 0 || array_b);
>> +
>> +	if (diff)
>> +		*diff = NULL;
>> +
>> +	for (int i = 0; i < array_a_len; i++) {
>> +		if (!array_contains(array_b, array_b_len, array_a[i])) {
>> +			if (diff) {
>> +				*diff = reallocarray(*diff, diff_len + 1,
>> sizeof(**diff));
>> +				igt_assert(*diff);
>> +				(*diff)[diff_len] = array_a[i];
>> +			}
>> +
>> +			diff_len++;
>> +		}
>> +	}
>> +
>> +	return diff_len;
>> +}
>> +
>> +/**
>> + * kms_wait_for_new_connectors() - Wait for new connector to appear
>> + *
>> + * @newly_connected: Out pointer returning the array of connectors currently
>> + *                   found connected
>> + * @already_connected: Input pointer to array of connectors previously
>> + *                     connected
>> + * @already_connected_count: Length of @already_connected
>> + * @drm_fd: DRM file descriptor
>> + *
>> + * Returns the number of connectors not in @already_connected and currently
>> + * found connected.
>> + */
>> +int kms_wait_for_new_connectors(uint32_t **newly_connected,
>> +				const uint32_t *already_connected,
>> +				int already_connected_count, int drm_fd)
>> +{
>> +	int newly_connected_count;
>> +	struct timespec start, end;
>> +
>> +	igt_assert(newly_connected);
>> +	igt_assert(drm_fd);
> 
> Are you sure 0 can't be set as DRM file descriptor?
> With that fixed you can add my R-by.
> 

No, replaced by igt_assert_fd, thanks!