[PATCH i-g-t 2/5] tests/intel/kms_mst_helper: add helper for MST-related functions

[Nautiyal, Ankit K]

On 2/3/2025 1:42 PM, Kunal Joshi wrote:
> Add helper to centralize commonly used MST-related logic.
> igt_find_all_mst_output_in_topology() enumerates MST outputs
> that share the same root connector id.
>
> Signed-off-by: Kunal Joshi <kunal1.joshi at intel.com>
> Reviewed-by: Jeevan B <jeevan.b at intel.com>
> ---
>   tests/intel/kms_dp_linktrain_fallback.c | 28 +++------------
>   tests/intel/kms_mst_helper.c            | 48 +++++++++++++++++++++++++
>   tests/intel/kms_mst_helper.h            | 10 ++++++
>   tests/meson.build                       |  1 +
>   4 files changed, 63 insertions(+), 24 deletions(-)
>   create mode 100644 tests/intel/kms_mst_helper.c
>   create mode 100644 tests/intel/kms_mst_helper.h
>
> diff --git a/tests/intel/kms_dp_linktrain_fallback.c b/tests/intel/kms_dp_linktrain_fallback.c
> index 415005774..bcfb2f0a0 100644
> --- a/tests/intel/kms_dp_linktrain_fallback.c
> +++ b/tests/intel/kms_dp_linktrain_fallback.c
> @@ -16,6 +16,7 @@
>   #include <sys/types.h>
>   #include "igt_sysfs.h"
>   #include "igt.h"
> +#include "kms_mst_helper.h"
>   
>   /**
>    * SUBTEST: dp-fallback
> @@ -47,28 +48,6 @@ typedef int (*condition_check_fn)(int drm_fd, igt_output_t *output);
>   
>   IGT_TEST_DESCRIPTION("Test link training fallback");
>   
> -static void find_mst_outputs(int drm_fd, data_t *data,
> -			     igt_output_t *output,
> -			     igt_output_t *mst_outputs[],
> -			     int *num_mst_outputs)
> -{
> -	int output_root_id, root_id;
> -	igt_output_t *connector_output;
> -
> -	output_root_id = igt_get_dp_mst_connector_id(output);
> -	/*
> -	 * If output is MST check all other connected output which shares
> -	 * same path and fill mst_outputs and num_mst_outputs
> -	 */
> -	for_each_connected_output(&data->display, connector_output) {
> -		if (!igt_check_output_is_dp_mst(connector_output))
> -			continue;
> -		root_id = igt_get_dp_mst_connector_id(connector_output);
> -		if (((*num_mst_outputs) < IGT_MAX_PIPES) && root_id == output_root_id)
> -			mst_outputs[(*num_mst_outputs)++] = connector_output;
> -	}
> -}
> -
>   static bool setup_mst_outputs(data_t *data, igt_output_t *mst_output[],
>   			      int *output_count)
>   {
> @@ -83,8 +62,9 @@ static bool setup_mst_outputs(data_t *data, igt_output_t *mst_output[],
>   		    traversed_mst_outputs[i] == data->output->config.connector->connector_id)
>   			return false;
>   
> -	find_mst_outputs(data->drm_fd, data, data->output,
> -			 mst_output, output_count);
> +       igt_assert_f(igt_find_all_mst_output_in_topology(data->drm_fd, &data->display, data->output,
> +							mst_output, output_count),
> +		    "Unable to find mst outputs\n");
>   
>   	for (i = 0; i < *output_count; i++) {
>   		output = mst_output[i];
> diff --git a/tests/intel/kms_mst_helper.c b/tests/intel/kms_mst_helper.c
> new file mode 100644
> index 000000000..9d52068f7
> --- /dev/null
> +++ b/tests/intel/kms_mst_helper.c
> @@ -0,0 +1,48 @@
> +#include "kms_mst_helper.h"
> +
> +/*
> + * @drm_fd: DRM file descriptor
> + * @display: pointer to an #igt_display_t structure
> + * @output: target output
> + * @mst_outputs: filled with mst output of same toplogy as @output
> + * @num_mst_outputs: filled with count of mst outputs found in topology
All below these seems to get added erroneously. Please remove them.
> + * @n_pipes: total number of pipes available
> + * @used_pipes_mask: pointer to a bitmask (in/out) of already-used pipes
> + * @master_pipes_mask: bitmask of valid "master" pipes
> + * @valid_pipes_mask: bitmask of valid (non-fused) pipes
> + *
> + * Assign pipes to outputs based on the number of required pipes.
> + * This function will assign 1, 2, or 4 consecutive pipes to each output.
> + * It will also mark the used pipes in the bitmask.
> + *

Need to fix the documentation, doesnt seem to match with what the 
function is doing.


> + * Returns: true if all outputs can be assigned successfully; false otherwise.

Generally bool is returned when we want to check a specific thing which 
has true or false answer.

In this case, we are trying to find mst outputs which can succeed or not 
depending on the config.

Better to return 0 in case of success and negative error code in case of 
failure.


> + */
> +bool igt_find_all_mst_output_in_topology(int drm_fd, igt_display_t *display,
> +					 igt_output_t *output,
> +					 igt_output_t *mst_outputs[],
> +					 int *num_mst_outputs)
> +{
> +	int output_root_id, root_id;
> +	igt_output_t *connector_output;
> +
> +	if (!igt_check_output_is_dp_mst(output))
> +		return false;
> +
> +	output_root_id = igt_get_dp_mst_connector_id(output);
> +	if (output_root_id == -EINVAL)
> +		return false;

Let this change be in a separate patch, in the 
kms_dp_linktrain_fallback.c, and then it will be simple code movement 
from one file to another without any functional change.


> +
> +	/*
> +	 * If output is MST, check all other connected output which shares
> +	 * same path and fill mst_outputs and num_mst_outputs
> +	 */
> +	for_each_connected_output(display, connector_output) {
> +		if (!igt_check_output_is_dp_mst(connector_output))
> +			continue;
> +
> +		root_id = igt_get_dp_mst_connector_id(connector_output);
> +		if (((*num_mst_outputs) < IGT_MAX_PIPES) && root_id == output_root_id)
> +			mst_outputs[(*num_mst_outputs)++] = connector_output;
> +	}
> +	return true;
> +}
> diff --git a/tests/intel/kms_mst_helper.h b/tests/intel/kms_mst_helper.h
> new file mode 100644
> index 000000000..291fcebfe
> --- /dev/null
> +++ b/tests/intel/kms_mst_helper.h
> @@ -0,0 +1,10 @@


Missing License header.

Regards,

Ankit

> +#ifndef KMS_MST_HELPER_H
> +#define KMS_MST_HELPER_H
> +
> +#include "igt.h"
> +
> +bool igt_find_all_mst_output_in_topology(int drm_fd, igt_display_t *display,
> +					 igt_output_t *output,
> +					 igt_output_t *mst_outputs[],
> +					 int *num_mst_outputs);
> +#endif
> diff --git a/tests/meson.build b/tests/meson.build
> index b2a7d7760..b9dd162cc 100644
> --- a/tests/meson.build
> +++ b/tests/meson.build
> @@ -367,6 +367,7 @@ extra_sources = {
>   	'kms_chamelium_frames': [ join_paths ('chamelium', 'kms_chamelium_helper.c') ],
>   	'kms_chamelium_hpd': [ join_paths ('chamelium', 'kms_chamelium_helper.c') ],
>   	'kms_dsc': [ join_paths ('intel', 'kms_dsc_helper.c') ],
> +        'kms_dp_linktrain_fallback': [ join_paths ('intel', 'kms_mst_helper.c') ],
>   	'kms_joiner': [ join_paths ('intel', 'kms_joiner_helper.c') ],
>   	'kms_psr2_sf':  [ join_paths ('intel', 'kms_dsc_helper.c') ],
>   }