ron minnich [mailto:rminnich@gmail.com] wrote:
]Thanks scott! ] ]So, what does an OS do to disable USB in the operating system? We have ]seen Linux do it, we're not quite sure just what ]place it gets done. ] ]ron
If I understand your question, I am not sure I know the answer. If you boot linux with grub option 'nousb', or reboot Windows after disabling usb controllers from device manager, what happens? I assume the operating system just ignores USB controllers. It seems unlikely that the OS would take some action to ensure that they are properly disabled. Does UEFI disable USB controllers before handoff to the OS loader? I do not know. Having the OS not load USB drivers should eliminate USB related interrupts, but I know EHCI can generate memory accesses even when idle.
Thanks, Scott