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

[Jeevan B <jeevan.b@intel.com>]

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.

v2: move fit_modes_in_bw to lib/igt_kms
v3: update tag from fixes to closes

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1542
Signed-off-by: Jeevan B <jeevan.b@intel.com>
---
 lib/igt_kms.c                           | 24 ++++++++++++++++++++++++
 lib/igt_kms.h                           |  1 +
 tests/intel/kms_dp_link_training.c      | 24 +-----------------------
 tests/intel/kms_dp_linktrain_fallback.c | 18 +-----------------
 tests/kms_display_modes.c               |  4 ++++
 5 files changed, 31 insertions(+), 40 deletions(-)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 99c8707c7..f8274f49a 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -5046,6 +5046,30 @@ bool igt_override_all_active_output_modes_to_fit_bw(igt_display_t *display)
 	return __override_all_active_output_modes_to_fit_bw(display, outputs, n_outputs, 0);
 }
 
+/*
+ * fit_modes_in_bw :
+ * @display: a pointer to an #igt_display_t structure
+ *
+ * Tries atomic TEST_ONLY commit; if it fails, overrides
+ * output modes to fit bandwidth.
+ */
+bool fit_modes_in_bw(igt_display_t *display)
+{
+	bool found;
+	int ret;
+
+	ret = igt_display_try_commit_atomic(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(display);
+		igt_require_f(found,
+			      "No valid mode combo found for modeset\n");
+	}
+
+	return true;
+}
+
 /**
  * igt_pipe_refresh:
  * @display: a pointer to an #igt_display_t structure
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 0381c82ad..fe01eaf3f 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1226,6 +1226,7 @@ void igt_require_pipe(igt_display_t *display,
 void igt_dump_connectors_fd(int drmfd);
 void igt_dump_crtcs_fd(int drmfd);
 bool igt_override_all_active_output_modes_to_fit_bw(igt_display_t *display);
+bool fit_modes_in_bw(igt_display_t *display);
 bool igt_get_i915_edp_lobf_status(int drmfd, char *connector_name);
 unsigned int igt_get_output_max_bpc(int drmfd, char *connector_name);
 unsigned int igt_get_pipe_current_bpc(int drmfd, enum pipe pipe);
diff --git a/tests/intel/kms_dp_link_training.c b/tests/intel/kms_dp_link_training.c
index 9e9b1e6db..9b6248c6f 100644
--- a/tests/intel/kms_dp_link_training.c
+++ b/tests/intel/kms_dp_link_training.c
@@ -140,28 +140,6 @@ static void setup_planes_fbs(data_t *data, igt_output_t *outs[],
 	}
 }
 
-/*
- * fit_modes_in_bw - Tries atomic TEST_ONLY commit; if it fails, overrides
- * output modes to fit bandwidth.
- */
-static bool fit_modes_in_bw(data_t *data)
-{
-	int ret;
-
-	ret = igt_display_try_commit_atomic(&data->display,
-					    DRM_MODE_ATOMIC_TEST_ONLY |
-					    DRM_MODE_ATOMIC_ALLOW_MODESET,
-					    NULL);
-	if (ret != 0) {
-		bool found;
-
-		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;
-}
-
 static void do_modeset(data_t *data, bool mst)
 {
 	uint32_t master_pipes_mask = 0;
@@ -204,7 +182,7 @@ static void do_modeset(data_t *data, bool mst)
 						  "Unable to assign pipes for outputs\n");
 
 	setup_planes_fbs(data, outs, out_count, modes, fbs, planes);
-	fit_modes_in_bw(data);
+	fit_modes_in_bw(&data->display);
 	igt_display_commit2(&data->display, COMMIT_ATOMIC);
 }
 
diff --git a/tests/intel/kms_dp_linktrain_fallback.c b/tests/intel/kms_dp_linktrain_fallback.c
index 6a872efd2..64f21ec6f 100644
--- a/tests/intel/kms_dp_linktrain_fallback.c
+++ b/tests/intel/kms_dp_linktrain_fallback.c
@@ -151,22 +151,6 @@ static void set_connector_link_status_good(data_t *data, igt_output_t *outputs[]
 							  DRM_MODE_LINK_STATUS_GOOD);
 }
 
-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;
-}
-
 static bool validate_modeset_for_outputs(data_t *data,
 					igt_output_t *outputs[],
 					int *output_count,
@@ -176,7 +160,7 @@ static bool validate_modeset_for_outputs(data_t *data,
 {
 	igt_require_f(*output_count > 0, "Require at least 1 output\n");
 	setup_pipe_on_outputs(data, outputs, output_count);
-	igt_assert_f(fit_modes_in_bw(data), "Unable to fit modes in bw\n");
+	igt_assert_f(fit_modes_in_bw(&data->display), "Unable to fit modes in bw\n");
 	setup_modeset_on_outputs(data, outputs,
 				 output_count,
 				 mode, fb, primary);
diff --git a/tests/kms_display_modes.c b/tests/kms_display_modes.c
index 588820170..f2bbfafe2 100644
--- a/tests/kms_display_modes.c
+++ b/tests/kms_display_modes.c
@@ -93,6 +93,8 @@ 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(display));
+
 	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 +140,7 @@ 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(display));
 	igt_display_commit2(display, COMMIT_ATOMIC);
 
 	igt_pipe_crc_collect_crc(pipe_crc[0], &crc[0]);
@@ -158,6 +161,7 @@ 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(display));
 	igt_display_commit2(display, COMMIT_ATOMIC);
 
 	/*Compare CRC*/
-- 
2.25.1