From: Alex Hung <[email protected]> [WHAT] Add KUnit tests for dm_handle_mst_sideband_msg_ready_event() covering the DOWN_REP ready bit that is acknowledged at DPCD and re-polled until the iteration limit, and the case where the acknowledge write keeps failing and the handler gives up after the third retry.
[HOW] A live topology manager is needed for the handler to reach its ack path, so the tests initialise one on a DRM device and arm the DOWN_REP ready bit in the fake DPCD. The fake AUX channel gains a separate write result so the ESI read still succeeds while the acknowledge write fails. Assisted-by: Copilot:Claude-Opus-5 Reviewed-by: Bhawanpreet Lakha <[email protected]> Signed-off-by: Alex Hung <[email protected]> Signed-off-by: Ivan Lipski <[email protected]> --- .../tests/amdgpu_dm_mst_types_test.c | 80 +++++++++++++++++++ 1 file changed, 80 insertions(+) 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 caedad4197bd9..6a5191f9baf61 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 @@ -38,6 +38,7 @@ static int dm_mst_test_aux_transfer_raw_result; static u8 dm_mst_test_aux_transfer_raw_reply; static enum aux_return_code_type dm_mst_test_aux_transfer_raw_operation_result; static ssize_t dm_mst_test_aux_transfer_override; +static ssize_t dm_mst_test_aux_write_override; static int dm_mst_test_aux_transfer_raw(struct ddc_service *ddc, struct aux_payload *payload, @@ -109,6 +110,8 @@ static ssize_t dm_mst_test_aux_transfer(struct drm_dp_aux *aux, msg->reply = DP_AUX_NATIVE_REPLY_ACK; return msg->size; case DP_AUX_NATIVE_WRITE: + if (dm_mst_test_aux_write_override) + return dm_mst_test_aux_write_override; msg->reply = DP_AUX_NATIVE_REPLY_ACK; return msg->size; default: @@ -146,6 +149,7 @@ static struct amdgpu_dm_connector *dm_mst_test_alloc_sideband_connector(struct k memset(dm_mst_test_dpcd, 0, sizeof(dm_mst_test_dpcd)); dm_mst_test_aux_transfer_override = 0; + dm_mst_test_aux_write_override = 0; return aconnector; } @@ -1339,6 +1343,80 @@ static void dm_mst_test_detect_unregistered(struct kunit *test) (int)connector_status_disconnected); } +/* + * Sideband connector with a live topology manager and the DOWN_REP ready bit + * armed, so dm_handle_mst_sideband_msg_ready_event() reaches its ack path. + */ +static struct amdgpu_dm_connector * +dm_mst_test_alloc_armed_sideband_connector(struct kunit *test) +{ + struct amdgpu_dm_connector *aconnector; + struct amdgpu_device *adev; + int ret; + + adev = dm_kunit_alloc_adev(test); + ret = drmm_mode_config_init(&adev->ddev); + KUNIT_ASSERT_EQ(test, ret, 0); + + aconnector = dm_mst_test_alloc_sideband_connector(test); + + ret = drm_dp_mst_topology_mgr_init(&aconnector->mst_mgr, &adev->ddev, + &aconnector->dm_dp_aux.aux, 16, 4, 0); + KUNIT_ASSERT_EQ(test, ret, 0); + aconnector->mst_mgr.mst_state = true; + dm_mst_test_dpcd[(DP_SINK_COUNT_ESI + 1) & 0xf] = DP_DOWN_REP_MSG_RDY; + + return aconnector; +} + +static void dm_mst_test_free_armed_sideband_connector(struct amdgpu_dm_connector *aconnector) +{ + aconnector->mst_mgr.mst_state = false; + drm_dp_mst_topology_mgr_destroy(&aconnector->mst_mgr); +} + +/** + * dm_mst_test_sideband_msg_ready_acks_down_rep - Test DOWN_REP ack handling + * @test: KUnit test context + * + * With an active topology manager and the DOWN_REP ready bit set, the sideband + * handler must acknowledge the event at DPCD and keep polling until the + * iteration limit is reached, since the fake sideband message never completes. + */ +static void dm_mst_test_sideband_msg_ready_acks_down_rep(struct kunit *test) +{ + struct amdgpu_dm_connector *aconnector; + + aconnector = dm_mst_test_alloc_armed_sideband_connector(test); + + dm_handle_mst_sideband_msg_ready_event(&aconnector->mst_mgr, DOWN_REP_MSG_RDY_EVENT); + + KUNIT_EXPECT_EQ(test, aconnector->mst_mgr.sink_count, 0); + + dm_mst_test_free_armed_sideband_connector(aconnector); +} + +/** + * dm_mst_test_sideband_msg_ready_ack_write_fails - Test failed DPCD ack + * @test: KUnit test context + * + * When the DPCD acknowledge write keeps failing, the sideband handler must give + * up after the third retry instead of looping forever. + */ +static void dm_mst_test_sideband_msg_ready_ack_write_fails(struct kunit *test) +{ + struct amdgpu_dm_connector *aconnector; + + aconnector = dm_mst_test_alloc_armed_sideband_connector(test); + dm_mst_test_aux_write_override = -EIO; + + dm_handle_mst_sideband_msg_ready_event(&aconnector->mst_mgr, DOWN_REP_MSG_RDY_EVENT); + + KUNIT_EXPECT_EQ(test, aconnector->mst_mgr.sink_count, 0); + + 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 @@ -1399,6 +1477,8 @@ static struct kunit_case dm_mst_types_test_cases[] = { KUNIT_CASE(dm_mst_test_sideband_msg_ready_no_ready_bits), KUNIT_CASE(dm_mst_test_sideband_msg_ready_read_error), KUNIT_CASE(dm_mst_test_sideband_msg_ready_without_mst_state), + KUNIT_CASE(dm_mst_test_sideband_msg_ready_acks_down_rep), + KUNIT_CASE(dm_mst_test_sideband_msg_ready_ack_write_fails), KUNIT_CASE(dm_mst_test_down_rep_msg_ready_wrapper), /* amdgpu_dm_initialize_dp_connector tests */ KUNIT_CASE(dm_mst_test_initialize_dp_connector_edp), -- 2.43.0
