Re: [PATCH i-g-t 03/14] lib/igt_kms: add function to get max link rate/lane count

[Imre Deak <imre.deak@intel.com>]

On Mon, Aug 26, 2024 at 01:36:01AM +0530, Kunal Joshi wrote:
> i915_dp_max_(lane_count/link_rate) debugfs files expose max link
> rate/lane count for connector.add function to get max link rate/lane
> lane count for connector
> 
> Signed-off-by: Kunal Joshi <kunal1.joshi@intel.com>
> ---
>  lib/igt_kms.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/igt_kms.h |  2 ++
>  2 files changed, 60 insertions(+)
> 
> diff --git a/lib/igt_kms.c b/lib/igt_kms.c
> index 4ef7f4d7f..21ea8550c 100644
> --- a/lib/igt_kms.c
> +++ b/lib/igt_kms.c
> @@ -6763,3 +6763,61 @@ enum dp_lane_count igt_get_dp_lane_count_set_for_output(int drm_fd, igt_output_t
>  
>  	return lane_count;
>  }
> +
> +/**
> + * igt_get_dp_max_link_rate:
> + * @drm_fd: A drm file descriptor
> + * @output: The output to query
> + *
> + * Get the max link rate supported by the sink.
> + *
> + * Returns: Max link rate supported by the sink.
> + */
> +enum dp_link_rate igt_get_dp_max_link_rate(int drm_fd, igt_output_t *output)
> +{
> +	char buf[512];
> +	int dir, res;
> +	int max_link_rate;
> +
> +	igt_require_f(output->name, "Invalid output");
> +	dir = igt_debugfs_connector_dir(drm_fd, output->name, O_DIRECTORY);
> +	igt_assert_f(dir >= 0, "Failed to open debugfs dir for connector %s\n",
> +				 igt_output_name(output));
> +	res = igt_debugfs_simple_read(dir, "i915_dp_max_link_rate",
> +								  buf, sizeof(buf));
> +	close(dir);
> +	igt_require_f(res > 0, "Couldn't read i915_dp_max_link_rate");
> +
> +	igt_assert(sscanf(buf, "%d", &max_link_rate) == 1);
> +
> +	return max_link_rate;
> +}

The comments from the previous patch apply here too. This makes me
wonder if it'd make more sense to add all these DP link training debugfs
entries from one patch.

> +
> +/**
> + * igt_get_dp_max_lane_count:
> + * @drm_fd: A drm file descriptor
> + * @output: The output to query
> + *
> + * Get the max lane count supported by the sink.
> + *
> + * Returns: Max lane count supported by the sink.
> + */
> +enum dp_lane_count igt_get_dp_max_lane_count(int drm_fd, igt_output_t *output)
> +{
> +	char buf[512];
> +	int dir, res;
> +	int max_lane_count;
> +
> +	igt_require_f(output->name, "Invalid output");
> +	dir = igt_debugfs_connector_dir(drm_fd, output->name, O_RDONLY);
> +	igt_assert_f(dir >= 0, "Failed to open debugfs dir for connector %s\n",
> +				 igt_output_name(output));
> +	res = igt_debugfs_simple_read(dir, "i915_dp_max_lane_count",
> +								  buf, sizeof(buf));
> +	close(dir);
> +	igt_require(res > 0);
> +
> +	igt_assert(sscanf(buf, "%d", &max_lane_count) == 1);
> +
> +	return max_lane_count;
> +}
> diff --git a/lib/igt_kms.h b/lib/igt_kms.h
> index 9d42a2b35..1d3226c5c 100644
> --- a/lib/igt_kms.h
> +++ b/lib/igt_kms.h
> @@ -1249,5 +1249,7 @@ int igt_get_dp_mst_connector_id(igt_output_t *output);
>  int get_num_scalers(igt_display_t *display, enum pipe pipe);
>  enum dp_link_rate igt_get_dp_link_rate_set_for_output(int drm_fd, igt_output_t *output);
>  enum dp_lane_count igt_get_dp_lane_count_set_for_output(int drm_fd, igt_output_t *output);
> +enum dp_link_rate igt_get_dp_max_link_rate(int drm_fd, igt_output_t *output);
> +enum dp_lane_count igt_get_dp_max_lane_count(int drm_fd, igt_output_t *output);
>  
>  #endif /* __IGT_KMS_H__ */
> -- 
> 2.34.1
>