On Fri, Dec 16, 2011 at 09:42:41PM +0100, Sebastian Andrzej Siewior wrote: > * Matthew Wilcox | 2011-12-16 15:31:46 [-0500]: > > >On Fri, Dec 16, 2011 at 09:12:36PM +0100, Sebastian Andrzej Siewior wrote: > >> * Sebastian Andrzej Siewior | 2011-12-16 15:47:24 [+0100]: > >> > >> >>If you want to take a stab at redoing your patch #2 to use only one > >> >>status URB for USB 2.0 devices, I would appreciate it. Then I can build > >> >>the abort/reset synchronization on top of it. > >> >Okay. > >> > >> Just once things started to become easy.... So while I tried to have > >> only one status urb which I always re-submit (as Matthew/ You suggested) > >> I run into the problem that I don't have struct scsi_device yet. So I > >> just created a device with two luns to see if this struct happens always > >> to be same. Ofcourse it is not. > > > >Can you not send one status URB per LUN (instead of one per command)? > > The thing is by the time a status URB completes I have only the *TAG* > number from the device which tells to which command it belongs. Sending > one status per LUN does not help because once a status URB with TAG 1 > arrived I have no idea to which device/LUN it does belong. ->context > does not help here at all. Oh, right, now I understand. With USB 2.0, we might have one status URB per LUN, but they're being queued to the same endpoint ring. Since the device can re-order the commands any way it likes, we can't rely on the scsi_device that's stored on the urb->context to be correct. Ok, I think we just need to divide the tag address space equally between devices. The devinfo can keep track of the pointers to the scsi_devices for each LUN, and what tag range each LUN has. So if you have 255 tags available, and two LUNs, you can give one of them tag 1 to 122, and the other tags 123 to 254. Sarah Sharp -- 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
