On Tuesday 11 December 2007, Alan Stern wrote: > Dave: > > I just tried doing some hibernation testing, and my external high-speed > hub is behaving very strangely. The test is simple. First plug in the > hub, then plug a flash drive into the hub to keep it from > autosuspending. Then: > > echo test >/sys/power/disk > echo disk >/sys/power/state > > The first line causes the hibernation to stop after the PM_EVENT_FREEZE > message has been sent; after that everything is woken back up. There > are no bus-power-level changes since the EHCI controller remains in D0 > throughout. > > This sequence causes the hub to disconnect and reconnect itself! When > khubd starts running again, it sees the port-connect-change event. > > This happens only with the hub; if I plug the flash drive into the > computer's USB port instead of plugging the hub there, the drive > remains connected at the end of the test. > > The hub doesn't disconnect itself like this during a runtime suspend. > In fact, if I run the hibernation test while the hub is already > suspended then there is no port-connect-change event and the hub can be > resumed normally. > > Do you have any idea how this could be happening? As far as I can > tell, the hub shouldn't be able to distinguish one sort of suspend from > another.
This doesn't ring any bells with me. It seems buglike. :) - Dave > > Alan Stern > - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
