Am Montag, 25. April 2011, 23:30:38 schrieb Alan Stern: > On Mon, 25 Apr 2011, Sarah Sharp wrote: > > > On Mon, Apr 25, 2011 at 03:18:46PM -0400, Alan Stern wrote: > > > On Mon, 25 Apr 2011, Sarah Sharp wrote: > > > > > > > Random question time. :) > > > > > > > > Do USB device drivers have to cancel all URBs that are pending for a > > > > device before calling usb_reset_device? Will the drivers have to wait > > > > for the URBs to complete before resetting the device? > > > > > > There is no requirement that drivers cancel all URBs before a reset > > > occurs. Indeed, some drivers can't because they have no way to know > > > when another driver bound to another interface on the same device wants > > > to do a reset, i.e., they have no pre_reset callback. > > > > 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. Then we should add it. If a driver does not implement pre_reset() we call disconnect() which does require termination of all IO. If we call pre_reset() any further IO is unreliable. The assumption they are making are quite reasonable. Regards Oliver -- 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
