within the first 4 bytes of the EHCI memory space. For controllers that
use big-endian MMIO, reading them with 1- and 2-byte reads would then
return the wrong values. Instead, read the combined register with a 4-byte
read and mask out the interesting quantities.
all host controllers at the same time, we avoid problems where the BIOS will
actually write to the USB registers of all the USB host controllers every time
we handover one of them, and consequently reset the OS programmed values.
Submitted by: avg
Reviewed by: jhb
