I am having a similar issue with IOBufferMemoryDescriptor::inTaskWithPhysicalMask. It seems like inTaskWithPhysicalMask does not allow the physicalMask to restrict the output address to only 32-bits on an M1 based mac. If I change the physicalMask to be 0xFFFFFF000 (>32 bits) then the inTaskWithPhysicalMask succeeds but now the hardware has an issue with the 64-bit addressing. Also, it would seem that setPreparationID is for user mode code, not Kernel. Have you found a way round this?

Care to share some example source on how you were able to do that? I am also using IODMACommand. However if the IOBufferMemoryDescriptor::inTaskWithPhysicalMask has the physicalMask set to 0xFFFFF000 (32 bits) then inTaskWithPhysicalMask fails and it wouldn't matter what IODMACommand does since you can't get there.

For those of you looking at this with the same problem, the answer was to add: <key>com.apple.security.temporary-exception.iokit-user-client-class</key> <array> <string>IOUserUserClient</string> </array> to the application's entitlement file. Apple is still trying to figure out why the example code didn't work "out-of-the-box". Thanks!

The IOUserAudioDevice::SetTransportType() function is what generally sets that icon for your device.