On Wed, 27 Jan 2010, Oliver Neukum wrote: > Am Mittwoch, 27. Januar 2010 15:55:32 schrieb Alan Stern: > > On Wed, 27 Jan 2010 mikedunn@xxxxxxxxxxx wrote: > > > > > Hi, > > > > > > Quick question that will save a lot of time slogging through usbcore code if > > > someone will indulge me. > > > > > > Is it necessary to kill all outstanding urbs in a driver's disconnect > > > function? I've seen documentation saying that the usbcore takes care of this > > > when the disconnect is detected, suggesting that tracking outstanding urbs and > > > killing them in the driver's disconnect function is unnecessary. But I also > > > see drivers that do just that. As I understand it, an urb killed by usbcore > > > will have its callback invoked, with the result code indicating that it was > > > killed, which the callback can handle gracefully. Any errors in my > > > understanding? > > > > That's basically right. A driver doesn't have to kill its own URBs, > > but it is considered good form to do so. > > Ehm, there's the small matter of disconnect by sysfs or usbfs. > Or module unload. The reason for calling the disconnect routine doesn't matter; the core first disables the interface's endpoints, meaning that pending URBs will fail with -ESHUTDOWN and new submissions will fail with -ENOENT. However URBs for endpoint 0 are unaffected -- the driver has to handle them on its own. 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
