Two real-hardware correctness fixes from the M20 list, both invisible
to QEMU's forgiving controller:
refreshMaxPacketSize0 existed only as a comment. The EP0 context kept
the SPEED-DEFAULT max packet size (full-speed: 8) even when the device
declares 16/32/64 — real controllers fault the very first full
descriptor read on the mismatch, which is the standing suspect for
full-speed mice dying on the user's PC. Enumeration now probes the
device descriptor's first 8 bytes (deliverable at any legal MPS0),
and issues Evaluate Context to correct EP0 before any longer transfer,
naming the failure and codes if the controller refuses.
And a USB2 port's PORTSC speed field is only meaningful once the port
reset ENABLES the port: the speed (and the MPS0 default derived from
it) is now sampled after the reset instead of trusting the connect-time
read.
Daniel Samson
d8cf533b73