drm/amd/display: Build MST DSC helpers for KUnit

[WHAT]
The MST DSC helpers in amdgpu_dm_mst_types.c are compiled only when
CONFIG_DRM_AMD_DC_FP is enabled, which no UML KUnit build can select,
so none of them can be reached from the KUnit suite.

[HOW]
Widen the CONFIG_DRM_AMD_DC_FP guards to also build when
CONFIG_DRM_AMD_DC_KUNIT_TEST is set. The only caller of
validate_dsc_caps_on_connector() is guarded as well, so guard it by
IS_ENABLED() instead to keep it out of the KUnit build while still
referencing the helper. With the real bodies now built,
dm_mst_test_fp_guarded_public_stubs() no longer describes reachable
behaviour, so remove it along with its case entry.

Assisted-by: Copilot:Claude-Opus-5
Reviewed-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Chenyu Chen <chen-yu.chen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 6 insertions, 25 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index bce605fd6cdf..aad8fff2cd6f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -278,7 +278,7 @@ bool needs_dsc_aux_workaround(struct dc_link *link)
 }
 EXPORT_IF_KUNIT(needs_dsc_aux_workaround);
 
-#if defined(CONFIG_DRM_AMD_DC_FP)
+#if defined(CONFIG_DRM_AMD_DC_FP) || IS_ENABLED(CONFIG_DRM_AMD_DC_KUNIT_TEST)
 static bool is_synaptics_cascaded_panamera(struct dc_link *link, struct drm_dp_mst_port *port)
 {
 	u8 branch_vendor_data[4] = { 0 }; // Vendor data 0x50C ~ 0x50F
@@ -504,8 +504,8 @@ STATIC_IFN_KUNIT int dm_dp_mst_get_modes(struct drm_connector *connector)
 		amdgpu_dm_update_freesync_caps(
 				connector, aconnector->drm_edid, true);
 
-#if defined(CONFIG_DRM_AMD_DC_FP)
-		if (!validate_dsc_caps_on_connector(aconnector))
+#if defined(CONFIG_DRM_AMD_DC_FP) || IS_ENABLED(CONFIG_DRM_AMD_DC_KUNIT_TEST)
+		if (IS_ENABLED(CONFIG_DRM_AMD_DC_FP) && !validate_dsc_caps_on_connector(aconnector))
 			memset(&aconnector->dc_sink->dsc_caps,
 			       0, sizeof(aconnector->dc_sink->dsc_caps));
 #endif
@@ -937,7 +937,7 @@ struct dsc_mst_fairness_params {
 	struct amdgpu_dm_connector *aconnector;
 };
 
-#if defined(CONFIG_DRM_AMD_DC_FP)
+#if defined(CONFIG_DRM_AMD_DC_FP) || IS_ENABLED(CONFIG_DRM_AMD_DC_KUNIT_TEST)
 static uint16_t get_fec_overhead_multiplier(struct dc_link *dc_link)
 {
 	u8 link_coding_cap;
@@ -1928,7 +1928,7 @@ static bool is_dsc_common_config_possible(struct dc_stream_state *stream,
 }
 #endif
 
-#if defined(CONFIG_DRM_AMD_DC_FP)
+#if defined(CONFIG_DRM_AMD_DC_FP) || IS_ENABLED(CONFIG_DRM_AMD_DC_KUNIT_TEST)
 static bool dp_get_link_current_set_bw(struct drm_dp_aux *aux, uint32_t *cur_link_bw)
 {
 	uint32_t total_data_bw_efficiency_x10000 = 0;
@@ -1990,7 +1990,7 @@ enum dc_status dm_dp_mst_is_port_support_mode(
 	struct amdgpu_dm_connector *aconnector,
 	struct dc_stream_state *stream)
 {
-#if defined(CONFIG_DRM_AMD_DC_FP)
+#if defined(CONFIG_DRM_AMD_DC_FP) || IS_ENABLED(CONFIG_DRM_AMD_DC_KUNIT_TEST)
 	int branch_max_throughput_mps = 0;
 	struct dc_link_settings cur_link_settings;
 	uint32_t end_to_end_bw_in_kbps = 0;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c
index 064af0022fb6..36d3f0eebb50 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c
@@ -2058,21 +2058,6 @@ static void dm_mst_test_sideband_msg_ready_ack_write_fails(struct kunit *test)
 	dm_mst_test_free_armed_sideband_connector(aconnector);
 }
 
-#if !defined(CONFIG_DRM_AMD_DC_FP)
-/**
- * dm_mst_test_fp_guarded_public_stubs - Test FP-off public fallbacks
- * @test: KUnit test context
- *
- * When CONFIG_DRM_AMD_DC_FP is disabled, the public DSC validation helper
- * has no FP body and must return DC_OK without touching its arguments.
- */
-static void dm_mst_test_fp_guarded_public_stubs(struct kunit *test)
-{
-	KUNIT_EXPECT_EQ(test, dm_dp_mst_is_port_support_mode(NULL, NULL),
-			(enum dc_status)DC_OK);
-}
-#endif
-
 static struct kunit_case dm_mst_types_test_cases[] = {
 	/* needs_dsc_aux_workaround tests */
 	KUNIT_CASE(dm_mst_test_needs_dsc_aux_workaround_match),
@@ -2152,10 +2137,6 @@ static struct kunit_case dm_mst_types_test_cases[] = {
 	/* dm_dp_mst_connector_destroy tests */
 	KUNIT_CASE(dm_mst_test_connector_destroy_no_sink),
 	KUNIT_CASE(dm_mst_test_connector_destroy_releases_sink),
-	/* CONFIG_DRM_AMD_DC_FP disabled public paths */
-#if !defined(CONFIG_DRM_AMD_DC_FP)
-	KUNIT_CASE(dm_mst_test_fp_guarded_public_stubs),
-#endif
 	{}
 };