On Mon, 13 Aug 2012, Peter Chen wrote: > Host controller's suspend should be executed later than root hub's, > or the hang may occur when root hub try to visit some registers > but host controller's suspend close the related clocks. Have you ever seen this happen? It should not be possible, because the PM core is careful not to suspend a parent before its child devices. > Mark controller's suspend as async can make sure it is executed > later than root hub's as host controller is the parent of root hub. We want to be careful about this sort of thing. Most of the async suspend notations are for devices on a particular kind of bus, but the notation you want to add would apply to all host controllers on any bus. If you really do see a host controller suspending before its root hub, this indicates there is a bug in the PM core. The bug should be fixed; you shouldn't ignore it by marking all host controllers for async suspend. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
