Re: [PATCH i-g-t] tests/intel/kms_dsc: Sort modes by clock to pick highest bandwidth mode

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 5/14/2026 1:42 AM, Swati Sharma wrote:
> Replace igt_output_get_highres_mode() with sort_drm_modes_by_clk_dsc()
> to select the mode with the highest pixel clock. When multiple modes
> share the same resolution but differ in refresh rate, the resolution-based
> sort is ambiguous and may pick the wrong mode. Sorting by clock descending
> ensures the highest bandwidth mode is selected, which is most likely to
> trigger DSC.
>
> Signed-off-by: Swati Sharma <swati2.sharma@intel.com>

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>


> ---
>   tests/intel/kms_dsc.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/tests/intel/kms_dsc.c b/tests/intel/kms_dsc.c
> index 69f335da3..605ad2d5c 100644
> --- a/tests/intel/kms_dsc.c
> +++ b/tests/intel/kms_dsc.c
> @@ -170,7 +170,12 @@ static void update_display(data_t *data, uint32_t test_type)
>   	igt_skip_on(!igt_plane_has_format_mod(primary, data->plane_format,
>   		    DRM_FORMAT_MOD_LINEAR));
>   
> -	mode = igt_output_get_highres_mode(output);
> +	/* Sort modes by clock descending to pick the highest bandwidth mode,
> +	 * which is most likely to trigger DSC. This handles cases where
> +	 * multiple modes share the same resolution but differ in refresh rate.
> +	 */
> +	igt_sort_connector_modes(output->config.connector, sort_drm_modes_by_clk_dsc);
> +	mode = &output->config.connector->modes[0];
>   
>   	do {
>   		if (data->output_format != DSC_FORMAT_RGB && index > 0)