[igt-dev] [PATCH v1 3/4] tests/kms_display_modes: Fixed mode selection for extended mode tests

[Mohammed Thasleem]

Added check on DP-MST and 4k panels when two moniters connected
through MST.
This will find the connector mode combo that fits into the
bandwidth when more than one monitor is connected.

Example:
  When two monitors connected through MST, the second monitor
  also tries to use the same mode. So two such modes may not
  fit into the link bandwidth. So, iterate through connected
  outputs & modes and find a combination of modes those fit
  into the link BW.

v2: -Updated commit msg and description. (Bhanu)
    -Renamed restart with retry. (Bhanu)
    -Moved igt_pipe_crc_new before retry. (Bhanu)
    -Removed unrelated changes and new line. (Bhanu)
    -Minor changes.
v3: Updated discription and added EINVAL check.
v4: Removed EINVAL and ENOSPC checks.
    Added check for DP-MST and 4k panels.
    Updated discription.
v5: Defined 4k display modes globally.
v6: -Removed if loop checks.
    -Added igt override to avoid dp mst bw failure.
Signed-off-by: Mohammed Thasleem <mohammed.thasleem at intel.com>
---
 tests/kms_display_modes.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/kms_display_modes.c b/tests/kms_display_modes.c
index 892f39b20..9f6f7a908 100644
--- a/tests/kms_display_modes.c
+++ b/tests/kms_display_modes.c
@@ -142,6 +142,7 @@ static void run_extendedmode_basic(data_t *data,
 	igt_pipe_crc_t *pipe_crc[2] = { 0 };
 	igt_crc_t ref_crc[2], crc[2];
 	int width, height;
+	bool found;
 	cairo_t *cr;
 
 	igt_display_reset(display);
@@ -171,6 +172,10 @@ static void run_extendedmode_basic(data_t *data,
 	igt_fb_set_size(&fbs[1], plane[1], mode[1]->hdisplay, mode[1]->vdisplay);
 	igt_plane_set_size(plane[1], mode[1]->hdisplay, mode[1]->vdisplay);
 
+	/* In case of DP-MST find suitable mode(s) to fit into the link BW. */
+	found = igt_override_all_active_output_modes_to_fit_bw(display);
+	igt_require_f(found, "No valid mode combo found for MST modeset.\n");
+
 	igt_display_commit2(display, COMMIT_ATOMIC);
 
 	igt_pipe_crc_collect_crc(pipe_crc[0], &ref_crc[0]);
-- 
2.25.1