[PATCH i-g-t 10/13] tests/intel/kms_dp_link_training: Add per connector mode subtests

[Kunal Joshi <kunal1.joshi@intel.com>]

The four existing subtests cover whichever connector mode the machine
presents. On a machine with a Thunderbolt dock they train a tunneled
link, on one without they train a direct link, and the result is
identical either way, so a lab that never had a dock looks the same as
one where the tunnel works.

Add eight subtests selecting links by connector mode:

	uhbr-sst-tbtalt-train        non-uhbr-sst-tbtalt-train
	uhbr-mst-tbtalt-train        non-uhbr-mst-tbtalt-train
	uhbr-sst-direct-train        non-uhbr-sst-direct-train
	uhbr-mst-direct-train        non-uhbr-mst-direct-train

with the same per configuration dynamic subtests as the existing ones.
"direct" is native, DP alt mode and legacy together: they all take the
link clock from the PHY PLL, and only tbt-alt takes it from the
Thunderbolt PLL, so that is the only split that changes which driver
code runs. The raw mode stays in the inventory line, so dp-alt against
legacy is still diagnosable from a failing run.

The connector mode has to be in the static subtest name rather than a
dynamic one, because a dynamic subtest that skips is not counted as
executed: a container with one pass and twenty skips reports PASS, so a
lab with no dock would look green.

Keep the four existing names and their PHY agnostic scope. They are not
redundant: they are what to run on a machine nobody provisioned for
this matrix.

Expect most of the eight to skip on any one machine, since dp-alt and
tbt-alt are mutually exclusive on a port at a given moment. The skip
reasons name the connector mode so the two causes - no such link, and a
link that allows no configuration in the encoding class - stay
greppable apart.

Assisted-by: GitHub_Copilot:claude-opus-5
Signed-off-by: Kunal Joshi <kunal1.joshi@intel.com>
---
 tests/intel/kms_dp_link_training.c | 142 ++++++++++++++++++++++++++++-
 1 file changed, 137 insertions(+), 5 deletions(-)

diff --git a/tests/intel/kms_dp_link_training.c b/tests/intel/kms_dp_link_training.c
index e6160cee5..229eb3d69 100644
--- a/tests/intel/kms_dp_link_training.c
+++ b/tests/intel/kms_dp_link_training.c
@@ -21,6 +21,40 @@
  * Description: Test we can drive non-UHBR rates over MST.
  */
 
+/**
+ * SUBTEST: uhbr-sst-tbtalt-train
+ * Description: Test we can drive UHBR rates over an SST link tunneled over
+ *              USB4/Thunderbolt.
+ *
+ * SUBTEST: uhbr-mst-tbtalt-train
+ * Description: Test we can drive UHBR rates over an MST link tunneled over
+ *              USB4/Thunderbolt.
+ *
+ * SUBTEST: uhbr-sst-direct-train
+ * Description: Test we can drive UHBR rates over a directly connected SST
+ *              link.
+ *
+ * SUBTEST: uhbr-mst-direct-train
+ * Description: Test we can drive UHBR rates over a directly connected MST
+ *              link.
+ *
+ * SUBTEST: non-uhbr-sst-tbtalt-train
+ * Description: Test we can drive non-UHBR rates over an SST link tunneled over
+ *              USB4/Thunderbolt.
+ *
+ * SUBTEST: non-uhbr-mst-tbtalt-train
+ * Description: Test we can drive non-UHBR rates over an MST link tunneled over
+ *              USB4/Thunderbolt.
+ *
+ * SUBTEST: non-uhbr-sst-direct-train
+ * Description: Test we can drive non-UHBR rates over a directly connected SST
+ *              link.
+ *
+ * SUBTEST: non-uhbr-mst-direct-train
+ * Description: Test we can drive non-UHBR rates over a directly connected MST
+ *              link.
+ */
+
 #include "i915/i915_dp.h"
 #include "igt.h"
 #include "igt_kms.h"
@@ -60,6 +94,38 @@ struct dp_link {
 	enum i915_dp_tc_mode tc_mode;
 };
 
+/*
+ * enum phy_filter - Which links a subtest selects.
+ *
+ * PHY_ANY is the PHY agnostic scope of the original subtests. The split
+ * between PHY_TBTALT and PHY_DIRECT is where the link clock comes from: only a
+ * tbt-alt link is clocked by the Thunderbolt PLL, native, DP alt mode and
+ * legacy all use the PHY PLL, so folding the latter three together does not
+ * change which driver code runs.
+ */
+enum phy_filter {
+	PHY_ANY,
+	PHY_TBTALT,
+	PHY_DIRECT,
+};
+
+static const char *phy_filter_name(enum phy_filter phy)
+{
+	return phy == PHY_TBTALT ? "tbt-alt" : "direct";
+}
+
+static bool link_matches_phy(const struct dp_link *link, enum phy_filter phy)
+{
+	switch (phy) {
+	case PHY_TBTALT:
+		return link->tc_mode == I915_DP_TC_TBT_ALT;
+	case PHY_DIRECT:
+		return link->tc_mode != I915_DP_TC_TBT_ALT;
+	default:
+		return true;
+	}
+}
+
 /*
  * check_condition_with_timeout - Polls check_fn until it returns 0
  * or until 'timeout' seconds elapse.
@@ -606,7 +672,8 @@ static int discover_links(data_t *data, struct dp_link *links, int max_links)
 	return num_links;
 }
 
-static bool test_link_rate(data_t *data, bool mst, bool uhbr)
+static bool test_link_rate(data_t *data, bool mst, bool uhbr,
+			   enum phy_filter phy)
 {
 	struct dp_link links[MAX_LINKS];
 	bool ran_any_link = false;
@@ -628,6 +695,15 @@ static bool test_link_rate(data_t *data, bool mst, bool uhbr)
 			continue;
 		}
 
+		if (!link_matches_phy(&links[i], phy)) {
+			igt_info("Skipping %s: %s requested but it's %s.\n",
+				 igt_output_name(links[i].output),
+				 phy_filter_name(phy),
+				 i915_dp_tc_mode_name(links[i].tc_mode));
+			igt_info("----------------------------------------------------\n");
+			continue;
+		}
+
 		data->output = links[i].output;
 		igt_info("Running link training test for %s\n",
 			 igt_output_name(data->output));
@@ -665,7 +741,7 @@ int igt_main()
 	igt_subtest_with_dynamic("uhbr-sst") {
 		igt_require_f(intel_display_ver(data.devid) > 13,
 			      "UHBR not supported on platform\n");
-		igt_require_f(test_link_rate(&data, false, true),
+		igt_require_f(test_link_rate(&data, false, true, PHY_ANY),
 			      "Didn't find any SST output with UHBR rates.\n");
 	}
 
@@ -673,22 +749,78 @@ int igt_main()
 	igt_subtest_with_dynamic("uhbr-mst") {
                 igt_require_f(intel_display_ver(data.devid) > 13,
                               "UHBR not supported on platform\n");
-		igt_require_f(test_link_rate(&data, true, true),
+		igt_require_f(test_link_rate(&data, true, true, PHY_ANY),
 			      "Didn't find any MST output with UHBR rates.\n");
 	}
 
 	igt_describe("Test we can drive NON-UHBR rates over SST");
 	igt_subtest_with_dynamic("non-uhbr-sst") {
-		igt_require_f(test_link_rate(&data, false, false),
+		igt_require_f(test_link_rate(&data, false, false, PHY_ANY),
 			      "Didn't find any SST output with NON-UHBR rates.\n");
 	}
 
 	igt_describe("Test we can drive NON-UHBR rates over MST");
 	igt_subtest_with_dynamic("non-uhbr-mst") {
-		igt_require_f(test_link_rate(&data, true, false),
+		igt_require_f(test_link_rate(&data, true, false, PHY_ANY),
 			      "Didn't find any MST output with NON-UHBR rates.\n");
 	}
 
+	igt_describe("Test we can drive UHBR rates over a tunneled SST link");
+	igt_subtest_with_dynamic("uhbr-sst-tbtalt-train") {
+		igt_require_f(intel_display_ver(data.devid) > 13,
+			      "UHBR not supported on platform\n");
+		igt_require_f(test_link_rate(&data, false, true, PHY_TBTALT),
+			      "No tbt-alt DP SST link allows a UHBR config\n");
+	}
+
+	igt_describe("Test we can drive UHBR rates over a tunneled MST link");
+	igt_subtest_with_dynamic("uhbr-mst-tbtalt-train") {
+		igt_require_f(intel_display_ver(data.devid) > 13,
+			      "UHBR not supported on platform\n");
+		igt_require_f(test_link_rate(&data, true, true, PHY_TBTALT),
+			      "No tbt-alt DP MST link allows a UHBR config\n");
+	}
+
+	igt_describe("Test we can drive UHBR rates over a direct SST link");
+	igt_subtest_with_dynamic("uhbr-sst-direct-train") {
+		igt_require_f(intel_display_ver(data.devid) > 13,
+			      "UHBR not supported on platform\n");
+		igt_require_f(test_link_rate(&data, false, true, PHY_DIRECT),
+			      "No direct DP SST link allows a UHBR config\n");
+	}
+
+	igt_describe("Test we can drive UHBR rates over a direct MST link");
+	igt_subtest_with_dynamic("uhbr-mst-direct-train") {
+		igt_require_f(intel_display_ver(data.devid) > 13,
+			      "UHBR not supported on platform\n");
+		igt_require_f(test_link_rate(&data, true, true, PHY_DIRECT),
+			      "No direct DP MST link allows a UHBR config\n");
+	}
+
+	igt_describe("Test we can drive non-UHBR rates over a tunneled SST link");
+	igt_subtest_with_dynamic("non-uhbr-sst-tbtalt-train") {
+		igt_require_f(test_link_rate(&data, false, false, PHY_TBTALT),
+			      "No tbt-alt DP SST link allows a non-UHBR config\n");
+	}
+
+	igt_describe("Test we can drive non-UHBR rates over a tunneled MST link");
+	igt_subtest_with_dynamic("non-uhbr-mst-tbtalt-train") {
+		igt_require_f(test_link_rate(&data, true, false, PHY_TBTALT),
+			      "No tbt-alt DP MST link allows a non-UHBR config\n");
+	}
+
+	igt_describe("Test we can drive non-UHBR rates over a direct SST link");
+	igt_subtest_with_dynamic("non-uhbr-sst-direct-train") {
+		igt_require_f(test_link_rate(&data, false, false, PHY_DIRECT),
+			      "No direct DP SST link allows a non-UHBR config\n");
+	}
+
+	igt_describe("Test we can drive non-UHBR rates over a direct MST link");
+	igt_subtest_with_dynamic("non-uhbr-mst-direct-train") {
+		igt_require_f(test_link_rate(&data, true, false, PHY_DIRECT),
+			      "No direct DP MST link allows a non-UHBR config\n");
+	}
+
 	igt_fixture() {
 		igt_reset_connectors();
 		igt_display_fini(&data.display);
-- 
2.25.1