}
 }
 
+static void cros_ec_proto_test_query_all_no_mkbp_return_error(struct kunit *test)
+{
+       struct cros_ec_proto_test_priv *priv = test->priv;
+       struct cros_ec_device *ec_dev = &priv->ec_dev;
+       struct ec_xfer_mock *mock;
+       int ret;
+
+       /* Set some garbage bytes. */
+       ec_dev->mkbp_event_supported = 0xbf;
+
+       /* For cros_ec_get_proto_info() without passthru. */
+       {
+               struct ec_response_get_protocol_info *data;
+
+               mock = cros_kunit_ec_xfer_mock_add(test, sizeof(*data));
+               KUNIT_ASSERT_PTR_NE(test, mock, NULL);
+
+               /*
+                * Although it doesn't check the value, provides valid sizes so that
+                * cros_ec_query_all() allocates din and dout correctly.
+                */
+               data = (struct ec_response_get_protocol_info *)mock->o_data;
+               data->max_request_packet_size = 0xbe;
+               data->max_response_packet_size = 0xef;
+       }
+
+       /* For cros_ec_get_proto_info() with passthru. */
+       {
+               mock = cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_INVALID_COMMAND, 0);
+               KUNIT_ASSERT_PTR_NE(test, mock, NULL);
+       }
+
+       /* For cros_ec_get_host_command_version_mask() for MKBP. */
+       {
+               mock = cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_INVALID_COMMAND, 0);
+               KUNIT_ASSERT_PTR_NE(test, mock, NULL);
+       }
+
+       cros_ec_proto_test_query_all_pretest(test);
+       ret = cros_ec_query_all(ec_dev);
+       KUNIT_EXPECT_EQ(test, ret, 0);
+
+       /* For cros_ec_get_proto_info() without passthru. */
+       {
+               mock = cros_kunit_ec_xfer_mock_next();
+               KUNIT_EXPECT_PTR_NE(test, mock, NULL);
+
+               KUNIT_EXPECT_EQ(test, mock->msg.version, 0);
+               KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_GET_PROTOCOL_INFO);
+               KUNIT_EXPECT_EQ(test, mock->msg.insize,
+                               sizeof(struct ec_response_get_protocol_info));
+               KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0);
+       }
+
+       /* For cros_ec_get_proto_info() with passthru. */
+       {
+               mock = cros_kunit_ec_xfer_mock_next();
+               KUNIT_EXPECT_PTR_NE(test, mock, NULL);
+
+               KUNIT_EXPECT_EQ(test, mock->msg.version, 0);
+               KUNIT_EXPECT_EQ(test, mock->msg.command,
+                               EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX) |
+                               EC_CMD_GET_PROTOCOL_INFO);
+               KUNIT_EXPECT_EQ(test, mock->msg.insize,
+                               sizeof(struct ec_response_get_protocol_info));
+               KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0);
+       }
+
+       /* For cros_ec_get_host_command_version_mask() for MKBP. */
+       {
+               struct ec_params_get_cmd_versions *data;
+
+               mock = cros_kunit_ec_xfer_mock_next();
+               KUNIT_EXPECT_PTR_NE(test, mock, NULL);
+
+               KUNIT_EXPECT_EQ(test, mock->msg.version, 0);
+               KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_GET_CMD_VERSIONS);
+               KUNIT_EXPECT_EQ(test, mock->msg.insize,
+                               sizeof(struct ec_response_get_cmd_versions));
+               KUNIT_EXPECT_EQ(test, mock->msg.outsize, sizeof(*data));
+
+               data = (struct ec_params_get_cmd_versions *)mock->i_data;
+               KUNIT_EXPECT_EQ(test, data->cmd, EC_CMD_GET_NEXT_EVENT);
+
+               KUNIT_EXPECT_EQ(test, ec_dev->mkbp_event_supported, 0);
+       }
+}
+
 static void cros_ec_proto_test_query_all_no_host_sleep(struct kunit *test)
 {
        struct cros_ec_proto_test_priv *priv = test->priv;
        KUNIT_CASE(cros_ec_proto_test_query_all_legacy_data_error),
        KUNIT_CASE(cros_ec_proto_test_query_all_legacy_return0),
        KUNIT_CASE(cros_ec_proto_test_query_all_no_mkbp),
+       KUNIT_CASE(cros_ec_proto_test_query_all_no_mkbp_return_error),
        KUNIT_CASE(cros_ec_proto_test_query_all_no_host_sleep),
        KUNIT_CASE(cros_ec_proto_test_query_all_default_wake_mask_return_error),
        {}