[throwaway5574]

> Yeah, the research is good. Software developers do not expect HCI to have this type of control. Because it's undocumented, it's not in their threat model and is unexpectedly available from userspace.

This possibility should be obvious to any software developer that knows how modern IO peripheral stacks are constructed. There is little that can be done to defend against a poorly written OS driver that exposes functions like this, even unintentionally, and it is naive to assume that any class of device will lack them unless clearly documented otherwise. This has been of particular concern to developers of open source Linux kernel drivers for decades at this point.