[PATCH i-g-t] tests/kms_display_modes: Fit modes within MST bandwidth constraints

[Sharma, Swati2]

Hi Jeevan,

On 24-03-2025 03:14 pm, Jeevan B wrote:
> Instead of checking only the current modes, find a combination of
> modes in the MST topology that can be accommodated within the
> available link bandwidth.
>
> Fixes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1542
> Signed-off-by: Jeevan B <jeevan.b at intel.com>
> ---
>   tests/kms_display_modes.c | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
>
> diff --git a/tests/kms_display_modes.c b/tests/kms_display_modes.c
> index 588820170..d1083f470 100644
> --- a/tests/kms_display_modes.c
> +++ b/tests/kms_display_modes.c
> @@ -49,6 +49,22 @@ typedef struct {
>   	int n_pipes;
>   } data_t;
>   
> +static bool fit_modes_in_bw(data_t *data)
> +{
> +	bool found;
> +	int ret;
> +
> +	ret = igt_display_try_commit_atomic(&data->display,
> +					    DRM_MODE_ATOMIC_TEST_ONLY |
> +					    DRM_MODE_ATOMIC_ALLOW_MODESET, NULL);
> +	if (ret != 0) {
> +		found = igt_override_all_active_output_modes_to_fit_bw(&data->display);
> +		igt_require_f(found,
> +			      "No valid mode combo found for modeset\n");
> +	}
> +	return true;
> +}
Lets have this function as part of lib.
> +
>   static bool output_is_dp_mst(data_t *data, igt_output_t *output, int i)
>   {
>   	int connector_id;
> @@ -93,6 +109,8 @@ static void run_extendedmode_basic(data_t *data,
>   	mode[0] = igt_output_get_mode(output1);
>   	mode[1] = igt_output_get_mode(output2);
>   
> +	igt_assert(fit_modes_in_bw(data));
> +
>   	pipe_crc[0] = igt_pipe_crc_new(data->drm_fd, pipe1, IGT_PIPE_CRC_SOURCE_AUTO);
>   	pipe_crc[1] = igt_pipe_crc_new(data->drm_fd, pipe2, IGT_PIPE_CRC_SOURCE_AUTO);
>   
> @@ -138,6 +156,7 @@ static void run_extendedmode_basic(data_t *data,
>   	igt_fb_set_size(&fb, plane[1], mode[1]->hdisplay, mode[1]->vdisplay);
>   	igt_plane_set_size(plane[1], mode[1]->hdisplay, mode[1]->vdisplay);
>   
> +	igt_assert(fit_modes_in_bw(data));
>   	igt_display_commit2(display, COMMIT_ATOMIC);
>   
>   	igt_pipe_crc_collect_crc(pipe_crc[0], &crc[0]);
> @@ -158,6 +177,7 @@ static void run_extendedmode_basic(data_t *data,
>   			  DRM_PLANE_TYPE_PRIMARY), NULL);
>   	igt_plane_set_fb(igt_pipe_get_plane_type(&display->pipes[pipe2],
>   			  DRM_PLANE_TYPE_PRIMARY), NULL);
> +	igt_assert(fit_modes_in_bw(data));
>   	igt_display_commit2(display, COMMIT_ATOMIC);
>   
>   	/*Compare CRC*/