Re: [PATCH i-g-t v9 07/49] lib/igt_kms: Add helper to get a pipe from a connector

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 16 Mar 2026, Louis Chauvet <louis.chauvet@bootlin.com> wrote:
> Currently there is no way to get a pipe from the connector. Add this tiny
> helper that will try to get the currently used pipe for a specific
> connector.
>
> Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  lib/igt_kms.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  lib/igt_kms.h |  3 +++
>  2 files changed, 44 insertions(+)
>
> diff --git a/lib/igt_kms.c b/lib/igt_kms.c
> index b220de419a70..1b34f5eb7ee7 100644
> --- a/lib/igt_kms.c
> +++ b/lib/igt_kms.c
> @@ -8419,3 +8419,44 @@ int kms_wait_for_new_connectors(uint32_t **newly_connected,
>  
>  	return newly_connected_count;
>  }
> +
> +/**
> + * igt_get_crtc_index_from_connector_id() - Get a pipe from the connector id
> + * @drm_fd: drm file descriptor to which the connector belongs
> + * @connector_id: connector to inspect
> + *
> + * Returns 0 if the connector is not connected to any pipe
> + */
> +int igt_get_crtc_index_from_connector_id(int drm_fd, int connector_id)
> +{
> +	drmModeObjectPropertiesPtr proplist;
> +	drmModePropertyPtr crtc_id_prop;
> +	drmModePropertyPtr prop;
> +	enum pipe crtc_index;

Pipes are pipes, CRTC indexes are indexes, and should not be conflated.

The CRTC index should just be an int.

BR,
Jani.

> +	uint32_t crtc_id;
> +	int i;
> +
> +	proplist = drmModeObjectGetProperties(drm_fd, connector_id, DRM_MODE_OBJECT_CONNECTOR);
> +	crtc_id_prop = NULL;
> +
> +	for (i = 0; i < proplist->count_props; i++) {
> +		prop = drmModeGetProperty(drm_fd, proplist->props[i]);
> +
> +		if (strcmp(prop->name, "CRTC_ID") == 0) {
> +			crtc_id_prop = prop;
> +			break;
> +		}
> +		drmModeFreeProperty(prop);
> +	}
> +
> +	igt_assert(crtc_id_prop);
> +	igt_assert((crtc_id_prop->flags & DRM_MODE_PROP_EXTENDED_TYPE) == DRM_MODE_PROP_OBJECT);
> +	crtc_id = proplist->prop_values[i];
> +	drmModeFreeProperty(crtc_id_prop);
> +	drmModeFreeObjectProperties(proplist);
> +	if (crtc_id != 0) {
> +		crtc_index = kmstest_get_crtc_index_from_id(drm_fd, crtc_id);
> +		return crtc_index;
> +	}
> +	return 0;
> +}
> diff --git a/lib/igt_kms.h b/lib/igt_kms.h
> index c6aae034b5b9..d346801e7915 100644
> --- a/lib/igt_kms.h
> +++ b/lib/igt_kms.h
> @@ -1314,4 +1314,7 @@ int kms_wait_for_new_connectors(uint32_t **newly_connected,
>  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 igt_get_crtc_index_from_connector_id(int drm_fd, int connector_id);
> +
>  #endif /* __IGT_KMS_H__ */

-- 
Jani Nikula, Intel