On Friday 04 January 2013 19:26:33 Dan Williams wrote: > On Fri, 2013-01-04 at 23:16 +0100, Oliver Neukum wrote: > > On Friday 04 January 2013 10:48:16 Dan Williams wrote: > > > Some drivers (ex sierra_net) need the status interrupt URB > > > active even when the device is closed, because they receive > > > custom indications from firmware. Allow sub-drivers to set > > > a flag that submits the status interrupt URB on probe and > > > keeps the URB alive over device open/close. The URB is still > > > killed/re-submitted for suspend/resume, as before. > > > > > > Signed-off-by: Dan Williams <dcbw@xxxxxxxxxx> > > > --- > > > Oliver: alternatively, is there a problem with *always* > > > submitting the interrupt URB, and then simply not calling > > > the subdriver's .status function when the netdev is > > > closed? That would be a much simpler patch. > > > > That is quite radical. We have no idea what a device > > does when we do not react to a status update. I would > > much prefer to not take the risk. > > Besides, we don't use bandwidth if we don't have to. > > Ok, so scratch the alternative. Thus, does the posted patch look like > the right course of action? In principle yes. > If I wasn't clear enough before, sierra_net needs to listen to the > status interrupt URB to receive the custom Restart indication as part of > the driver's device setup. Thus for sierra_net at least, tying the > status interrupt URB submission to device open/close isn't right. So, there seems to be an inevitable race before probe() is called. Have you looked at FLAG_AVOID_UNLINK_URBS ? > I'd previously done a patch to handle this all in sierra_net, but the > problem there is suspend/resume: without directly accessing the usbnet > structure's ->suspend_count member (icky!) sierra_net can't correctly > kill/submit the URB itself. So I went with a flag to usbnet that Sierra > can set. That is absolutely the right way to do it. 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
