On Thu, 8 Jul 2010, Sarah Sharp wrote: > One small thing I noticed is that this changes what the xHCI driver does > with urb->status. I think that the host driver isn't supposed to > directly set urb->status. I think the host driver is only supposed to pass the > status to usb_hcd_giveback_urb(). That's right. As far as the HCD is concerned, urb->status doesn't exist. In fact at one point we were considering removing it, but it turned out to be used by too many drivers. > The problem is that drivers aren't supposed to look at urb->status > until their completion function is called, but I think some of them > still might. So if the URB generates multiple events, the driver might > see the change of status for the first event and deallocate the URB > before the xHCI host has a chance to deal with the second event. I > think it's best to let the USB core handle setting urb->status. > > I did a quick grep for "urb->status", and none of the major hosts (EHCI, > UHCI, OHCI) directly set urb->status. There are a few embedded ones > (fhci, imx21, isp1362, isp1760, & oxu210hp), but I have no idea if > they're doing the correct thing. They aren't. I removed all the usages of urb->status in the HCDs at the time of the changeover, but some new ones may have been added since then. 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
