Yeah, I was not using large enough dx/dy values as I should have been.

Ha! That fixed it. How embarrassing. However, I'd expected a dialogue presented by the macOS or MusicKit asking for access to the Media library, similar to iOS, and it doesn't seem usable to ship something that requires the user to add the app to that list manually. Thank you!

Sorry, it's been a few days since I did this, but I should mention that I created an App Id with MusicKit enabled, and am signing the app with a provisioning profile created for that App Id.

Seems sort of reasonable, but those are valuable commodities!

It doesn’t appear that there is, but, if you’re interested in workarounds, you can use the boot arg “dk=0x8001”, which disables DriverKit entitlement checks.

After a bit more experimenting, I found that my test dx/dy values are not large enough or need to be shifted left some amount, but the test program works as expected.

After a bit more experimenting, I found that my test dx/dy values are not large enough or need to be shifted left some amount, but the test program works as expected.

Thanks! I've been checking regularly, and still no luck. Worked around it with the "dk" boot flag for now, and it's just for a personal project, so it's not that big of a deal. I guess I got lucky with my first request, which was approved in a few days.

Yeah, they do come from the kernel, at least as far as I can tell. Thank you, Quinn, I appreciate the information. Actually, having a predicate on "DK:" at the beginning would also seem to work well enough. Maybe after I get some more experience, I'll file that enhancement request, but as this is my first time writing a driver I'm not sure if what I need, or think I need, would be useful to others.