drm/amd/display: Add KUnit tests for dm_ism_dispatch_next_event

[Why & How]
Add 6 KUnit test cases exercising the new helper:

- hyst_wait_no_delay: HYSTERESIS_WAITING + delay_ns==0
  returns IMMEDIATE (covers null stream / no hysteresis config).
- hyst_wait_with_delay: HYSTERESIS_WAITING + delay_ns>0
  returns DM_ISM_NUM_EVENTS (timer scheduled, no immediate event).
- opt_idle_no_sso_delay: OPTIMIZED_IDLE + sso_delay_ns==0
  returns IMMEDIATE (skip SSO, transition immediately).
- opt_idle_with_sso_delay: OPTIMIZED_IDLE + sso_delay_ns>0
  returns DM_ISM_NUM_EVENTS (SSO timer scheduled).
- timer_aborted: TIMER_ABORTED always returns IMMEDIATE
  regardless of delay values.
- no_action_state: all other states return DM_ISM_NUM_EVENTS.

Assisted-by: Copilot:Claude-Sonnet-4.6
Reviewed-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_ism_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_ism_test.c
index c333dab40959..f3b3f77aafd5 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_ism_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_ism_test.c
@@ -781,6 +781,86 @@ static void dm_test_ism_trigger_event_invalid_transition(struct kunit *test)
 			(int)DM_ISM_STATE_FULL_POWER_RUNNING);
 }
 
+/* ===== Tests for dm_ism_dispatch_next_event ===== */
+
+/**
+ * dm_test_dispatch_next_event_hyst_wait_no_delay - zero delay_ns: IMMEDIATE in HYSTERESIS_WAITING
+ * @test: KUnit test context
+ */
+static void dm_test_dispatch_next_event_hyst_wait_no_delay(struct kunit *test)
+{
+	enum amdgpu_dm_ism_event result;
+
+	result = dm_ism_dispatch_next_event(DM_ISM_STATE_HYSTERESIS_WAITING,
+					    0, 0);
+	KUNIT_EXPECT_EQ(test, (int)result, (int)DM_ISM_EVENT_IMMEDIATE);
+}
+
+/**
+ * dm_test_dispatch_next_event_hyst_wait_with_delay - delay_ns > 0, no IMMEDIATE event returned
+ * @test: KUnit test context
+ */
+static void dm_test_dispatch_next_event_hyst_wait_with_delay(struct kunit *test)
+{
+	enum amdgpu_dm_ism_event result;
+
+	result = dm_ism_dispatch_next_event(DM_ISM_STATE_HYSTERESIS_WAITING,
+					    1000000, 0);
+	KUNIT_EXPECT_EQ(test, (int)result, (int)DM_ISM_NUM_EVENTS);
+}
+
+/**
+ * dm_test_dispatch_next_event_opt_idle_no_sso_delay - sso_delay_ns == 0 triggers IMMEDIATE event
+ * @test: KUnit test context
+ */
+static void dm_test_dispatch_next_event_opt_idle_no_sso_delay(struct kunit *test)
+{
+	enum amdgpu_dm_ism_event result;
+
+	result = dm_ism_dispatch_next_event(DM_ISM_STATE_OPTIMIZED_IDLE,
+					    0, 0);
+	KUNIT_EXPECT_EQ(test, (int)result, (int)DM_ISM_EVENT_IMMEDIATE);
+}
+
+/**
+ * dm_test_dispatch_next_event_opt_idle_with_sso_delay - sso_delay_ns > 0, SSO timer, no IMMEDIATE
+ * @test: KUnit test context
+ */
+static void dm_test_dispatch_next_event_opt_idle_with_sso_delay(struct kunit *test)
+{
+	enum amdgpu_dm_ism_event result;
+
+	result = dm_ism_dispatch_next_event(DM_ISM_STATE_OPTIMIZED_IDLE,
+					    0, 1000000);
+	KUNIT_EXPECT_EQ(test, (int)result, (int)DM_ISM_NUM_EVENTS);
+}
+
+/**
+ * dm_test_dispatch_next_event_timer_aborted - TIMER_ABORTED always returns IMMEDIATE
+ * @test: KUnit test context
+ */
+static void dm_test_dispatch_next_event_timer_aborted(struct kunit *test)
+{
+	enum amdgpu_dm_ism_event result;
+
+	result = dm_ism_dispatch_next_event(DM_ISM_STATE_TIMER_ABORTED,
+					    0, 0);
+	KUNIT_EXPECT_EQ(test, (int)result, (int)DM_ISM_EVENT_IMMEDIATE);
+}
+
+/**
+ * dm_test_dispatch_next_event_no_action_state - other states return DM_ISM_NUM_EVENTS
+ * @test: KUnit test context
+ */
+static void dm_test_dispatch_next_event_no_action_state(struct kunit *test)
+{
+	enum amdgpu_dm_ism_event result;
+
+	result = dm_ism_dispatch_next_event(DM_ISM_STATE_FULL_POWER_RUNNING,
+					    0, 0);
+	KUNIT_EXPECT_EQ(test, (int)result, (int)DM_ISM_NUM_EVENTS);
+}
+
 static struct kunit_case dm_ism_test_cases[] = {
 	/* dm_ism_next_state — FULL_POWER_RUNNING */
 	KUNIT_CASE(dm_test_ism_next_state_running_enter_idle),
@@ -836,6 +916,13 @@ static struct kunit_case dm_ism_test_cases[] = {
 	/* dm_ism_trigger_event */
 	KUNIT_CASE(dm_test_ism_trigger_event_valid_transition),
 	KUNIT_CASE(dm_test_ism_trigger_event_invalid_transition),
+	/* dm_ism_dispatch_next_event */
+	KUNIT_CASE(dm_test_dispatch_next_event_hyst_wait_no_delay),
+	KUNIT_CASE(dm_test_dispatch_next_event_hyst_wait_with_delay),
+	KUNIT_CASE(dm_test_dispatch_next_event_opt_idle_no_sso_delay),
+	KUNIT_CASE(dm_test_dispatch_next_event_opt_idle_with_sso_delay),
+	KUNIT_CASE(dm_test_dispatch_next_event_timer_aborted),
+	KUNIT_CASE(dm_test_dispatch_next_event_no_action_state),
 	{}
 };