On Wed, 3 Jul 2013, Laurent Pinchart wrote: > > Of course, it has been true all along that the status fields in the URB's > > individual usb_iso_packet_descriptor structures indicate any errors. But > > HCDs tend to set urb->status to 0 always, for isochronous URBs. Is there > > any advantage to setting urb->status to -EXDEV, given that we already set > > urb->iso_frame_desc[i].status to -EXDEV for each i? > > Not that I see, for the uvcvideo driver at least.
And probably not for anybody else either. > > With (2) or (3), the driver could also recover right away by setting > > the URB_ISO_ASAP flag on its next URB, but then synchronization would > > be lost. You wouldn't want to do this if synchronization matters. > > But if it doesn't, the driver could simply set URB_ISO_ASAP on every > > URB to avoid worrying about the problem -- the flag would have no > > effect in the absence of underruns. > > That's what the uvcvideo driver does. This could be changed, but I don't have > time to investigate at the moment. (Tested) patches are of course welcome :-) Based on your earlier comments, it sounds like always using URB_ISO_ASAP will do just what uvcvideo wants. Thanks for your feedback, Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
