> Usually very fast. Unfortunately for some kinds of USB host controllers > it can be relatively slow, since quiescing the controller has an > unavoidable side effect of suspending all devices on the bus. I wonder if we need to quiesce the controller in fact for FREEZE. Probably not. Just stop all queue processing and refuse URBs. The hcca will still get updated, but who cares ? it will end up beeing saved in an inconsistent state in the suspend image, so what ? On resume, we will have rebooted, we can "clean it up". This is sort-of breaking the rule of "no DMA", and thus is not suitable for kexec (which is ok, kexec currently uses the separate "shutdown" callback which must switch DMA off), but would fix the problem for suspend to disk... Ben.
