This is really cool! I like the name, too. Of all the things you've implemented for this, what has been the most difficult part? And have you hit any serious roadblocks along the way?
There hasn't been any overly difficult parts. I'd say the most difficult one has to be either AML interpreter because the ACPI specs are very badly written or the USB stack just because the size of the specifications is so large with a lot of cross referencing.
There hasn't been any major roadblocks. Sometimes I give up on a feature and come back to it maybe month or two later though.
My current one is really bad. It does work on maybe 50% of the hardware I have tested. I am in the middle on writing a new proper one, it is already way better but still missing some necessary parts before I can integrate it.
I would anticipate that you only have support for boot-mode keyboard and mouse now, considering the complexity of the full USB-HID spec. Otherwise I'd be very impressed.
I do actually support USB keyboard and mouse with USB-HID. There are some parts I don't support, like mouse specifying its movement with physical units (I haven't encountered any of those yet). Also I only have support for xHCI USB controller so PC's with older UHCI, EHCI or AHCI controllers are not yet supported.
There hasn't been any major roadblocks. Sometimes I give up on a feature and come back to it maybe month or two later though.