How to know if Disk.sys on stack

Hi all,

I am writing a disk upper filter driver. When starting my device, I want to know if Microsoft disk class driver was already loaded (instead of some other class drivers that kick out disk.sys, like EmcpBase.sys for virtual devices.)
I tried the IoOpenDeviceRegistryKey and looked for “ProviderName” that matches “Microsoft” but for some reason the call failed (0x00000034)

Is there a better way?

Regards,

Peter Trinh