[PATCH 37/70] drm/amd/display: add KUnit tests for stutter quirk

From: Alex Hung <[email protected]>

[WHAT]
Add KUnit tests for dm_should_disable_stutter covering a full quirk
match, a non-matching device, and a partial match that differs only in
the PCI revision.

Assisted-by: Copilot:Claude-Opus-4.8
Reviewed-by: Bhawanpreet Lakha <[email protected]>
Signed-off-by: Alex Hung <[email protected]>
Signed-off-by: Wayne Lin <[email protected]>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  3 +-
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  2 +
 .../display/amdgpu_dm/tests/amdgpu_dm_test.c  | 64 +++++++++++++++++++
 3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 8fe7e125e14a..8195ca386419 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -424,7 +424,7 @@ static const struct amdgpu_stutter_quirk amdgpu_stutter_quirk_list[] = {
 	{ 0, 0, 0, 0, 0 },
 };
 
-static bool dm_should_disable_stutter(struct pci_dev *pdev)
+STATIC_IFN_KUNIT bool dm_should_disable_stutter(struct pci_dev *pdev)
 {
 	const struct amdgpu_stutter_quirk *p = amdgpu_stutter_quirk_list;
 
@@ -440,6 +440,7 @@ static bool dm_should_disable_stutter(struct pci_dev *pdev)
 	}
 	return false;
 }
+EXPORT_IF_KUNIT(dm_should_disable_stutter);
 
 
 void*
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 897434504459..84c0bcfc093f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -1178,6 +1178,8 @@ bool is_dc_timing_adjust_needed(struct dm_crtc_state *old_state,
 				struct dm_crtc_state *new_state);
 void set_multisync_trigger_params(struct dc_stream_state *stream);
 void set_master_stream(struct dc_stream_state *stream_set[], int stream_count);
+struct pci_dev;
+bool dm_should_disable_stutter(struct pci_dev *pdev);
 void reset_freesync_config_for_crtc(struct dm_crtc_state *new_crtc_state);
 void get_freesync_config_for_crtc(struct dm_crtc_state *new_crtc_state,
 				  struct dm_connector_state *new_con_state);
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
index b988198418c6..dfdef08343a4 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
@@ -1937,6 +1937,66 @@ static void dm_test_per_frame_master_sync_skips_null_stream(struct kunit *test)
 			    stream);
 }
 
+/* Tests for dm_should_disable_stutter() */
+
+/**
+ * dm_test_should_disable_stutter_match - Test the quirk device matches
+ * @test: The KUnit test context
+ */
+static void dm_test_should_disable_stutter_match(struct kunit *test)
+{
+	struct pci_dev *pdev;
+
+	pdev = kunit_kzalloc(test, sizeof(*pdev), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, pdev);
+
+	pdev->vendor = 0x1002;
+	pdev->device = 0x15dd;
+	pdev->subsystem_vendor = 0x1002;
+	pdev->subsystem_device = 0x15dd;
+	pdev->revision = 0xc8;
+
+	KUNIT_EXPECT_TRUE(test, dm_should_disable_stutter(pdev));
+}
+
+/**
+ * dm_test_should_disable_stutter_no_match - Test a non-quirk device does not match
+ * @test: The KUnit test context
+ */
+static void dm_test_should_disable_stutter_no_match(struct kunit *test)
+{
+	struct pci_dev *pdev;
+
+	pdev = kunit_kzalloc(test, sizeof(*pdev), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, pdev);
+
+	pdev->vendor = 0x1002;
+	pdev->device = 0x1234;
+
+	KUNIT_EXPECT_FALSE(test, dm_should_disable_stutter(pdev));
+}
+
+/**
+ * dm_test_should_disable_stutter_revision_differs - Test a partial match (revision) fails
+ * @test: The KUnit test context
+ */
+static void dm_test_should_disable_stutter_revision_differs(struct kunit *test)
+{
+	struct pci_dev *pdev;
+
+	pdev = kunit_kzalloc(test, sizeof(*pdev), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, pdev);
+
+	/* Everything matches the quirk except the revision */
+	pdev->vendor = 0x1002;
+	pdev->device = 0x15dd;
+	pdev->subsystem_vendor = 0x1002;
+	pdev->subsystem_device = 0x15dd;
+	pdev->revision = 0x00;
+
+	KUNIT_EXPECT_FALSE(test, dm_should_disable_stutter(pdev));
+}
+
 static struct kunit_case amdgpu_dm_tests[] = {
 	/* Simple DM callbacks */
 	KUNIT_CASE(dm_test_is_idle),
@@ -2042,6 +2102,10 @@ static struct kunit_case amdgpu_dm_tests[] = {
 	KUNIT_CASE(dm_test_per_frame_master_sync_single_stream),
 	KUNIT_CASE(dm_test_per_frame_master_sync_two_streams),
 	KUNIT_CASE(dm_test_per_frame_master_sync_skips_null_stream),
+	/* dm_should_disable_stutter */
+	KUNIT_CASE(dm_test_should_disable_stutter_match),
+	KUNIT_CASE(dm_test_should_disable_stutter_no_match),
+	KUNIT_CASE(dm_test_should_disable_stutter_revision_differs),
 	{}
 };
 
-- 
2.43.0