On Wed, 27 Apr 2011, Ming Lei wrote: > 2011/4/26 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>: > >> Ah, ok. Apparently Windows recommends canceling all outstanding > >> transfers before issuing a port reset, which was apparently what the > >> chipset folks were hoping Linux also suggested. Oh well. > > > > I don't know offhand of any drivers that leave URBs active while doing > > a reset. But there's no recommendation about it. > > Seems it is not needed, see pg. 38 of ehci spec 1.0: > > Note: when software writes this bit(Port Reset bit) to a one, it must also > write a zero to the Port Enable bit. > > The ehci hcd has obeyed the rule already, which means downstream > propagation of data is blocked for the port except reset signal. It's true that the port is disabled while the reset is taking place. But that isn't what the original question asked about -- the original question was whether we allow URBs to remain active during the reset. 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
