By checking Ubuntu, there is no ‘/sys/subsystem’ in sysfs. To compatible with Ubuntu, delete the 'subsystem' creation in Linux compatible module.
On the other hand, the sysfs ‘/sys/subsystem’ cause failure for some Linux udev cases.
In Linux udev source code, there is a function named ‘scan_devices_all’, and it will scan ‘/sys/subsystem’ if it is existed, but now there are nothing in /sys/subsystem ‘, and it returns empty to cause some use cases failed.
To compatible with Linux Applications, suggest to remove 'subsystem' to match Ubuntu behavior.