On Mon, 7 Dec 2009, Linus Torvalds wrote: > I also suspect that even if you do the USB host controller suspend > synchronously, doing the actual USB devices asynchronously would still > help - even if it's only "asynchronously per bus" thing. > > So in fact, it's probably a good first step to start off doing only the > USB devices, not the controller. Interesting you should say that. The patch I asked Arjan to test involved not suspending USB devices at all (root hubs being the exception). That is in fact just what we do when CONFIG_USB_SUSPEND isn't set. There's no need to suspend the individual devices when the whole system is going down. They will automatically suspend when the controller stops sending out SOF packets, which occurs when the root hub is suspended. The USB spec describes this, grandiosely, as a "global suspend". But yes, I agree. Doing just the USB devices is a good first step. Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
