[i-g-t V2 3/3] tests/kms_color: Skip if current & requested BPC doesn't match

[Bhanuprakash Modem]

The "max bpc" property only ensures that the bpc will not go beyond
the value set through this property. It does not guarantee that the
same bpc will be used for the given mode.

If clock/bandwidth constraints permit, the max bpc will be used to
show the mode, otherwise the bpc will be reduced. So, if we really
want a particular bpc set, we can try reducing the resolution, till
we get the bpc that we set in max bpc property.

This patch will skip the test, if there is no valid resolution to get
the same bpc as set by max_bpc property.

V2:
* Refactor the logic

Cc: Swati Sharma <swati2.sharma at intel.com>
CC: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
---
 tests/kms_color.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/tests/kms_color.c b/tests/kms_color.c
index 93957f50..69d92539 100644
--- a/tests/kms_color.c
+++ b/tests/kms_color.c
@@ -635,6 +635,28 @@ static void test_pipe_limited_range_ctm(data_t *data,
 }
 #endif
 
+static bool i915_clock_constraint(data_t *data, enum pipe pipe, int bpc)
+{
+	igt_output_t *output = data->output;
+	drmModeConnector *connector = output->config.connector;
+
+	igt_sort_connector_modes(connector, sort_drm_modes_by_clk_dsc);
+
+	for_each_connector_mode(output) {
+		igt_output_override_mode(output, &connector->modes[i__]);
+		igt_display_commit(&data->display);
+
+		if (!igt_check_output_bpc_equal(data->drm_fd, pipe,
+						data->output->name, bpc))
+			continue;
+
+		return true;
+	}
+
+	igt_output_override_mode(output, NULL);
+	return false;
+}
+
 static void
 prep_pipe(data_t *data, enum pipe p)
 {
@@ -898,10 +920,9 @@ run_tests_for_pipe(data_t *data, enum pipe p)
 			igt_output_set_prop_value(output, IGT_CONNECTOR_MAX_BPC, 10);
 			igt_display_commit(&data->display);
 
-			if (!igt_check_output_bpc_equal(data->drm_fd, p, output->name, 10)) {
-				igt_output_set_prop_value(output, IGT_CONNECTOR_MAX_BPC, max_bpc);
-				igt_fail_on_f(true, "Failed to set max_bpc as: 10\n");
-			}
+			if (is_i915_device(data->drm_fd) &&
+			    !i915_clock_constraint(data, p, 10))
+				continue;
 
 			igt_dynamic_f("gamma-%s", output->name) {
 				ret = test_pipe_gamma(data, primary);
-- 
2.35.1