On 06.03.2015 21:05, Aleksander Morgado wrote: > On Fri, Mar 6, 2015 at 7:08 PM, Sergei Shtylyov > <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> wrote: >> Hello. >> >> On 03/06/2015 06:14 PM, Mathias Nyman wrote: >> >>> From: Aleksander Morgado <aleksander@xxxxxxxxxxxxx> >> >> >>> When a control transfer has a short data stage, the xHCI controller >>> generates >>> two transfer events: a COMP_SHORT_TX event that specifies the >>> untransferred >>> amount, and a COMP_SUCCESS event. But when the data stage is not short, >>> only the >>> COMP_SUCCESS event occurs. Therefore, xhci-hcd must set urb->actual_length >>> to >>> urb->transfer_buffer_length while processing the COMP_SUCCESS event, >>> unless >>> urb->actual_length was set already by a previous COMP_SHORT_TX event. >> >> >>> The driver checks this by seeing whether urb->actual_length == 0, but this >>> alone >>> is the wrong test, as it is entirely possible for a short transfer to have >>> an >>> urb->actual_length = 0. >> >> >>> This patch changes the xhci driver to rely on a new td->urb_length_set >>> flag, >>> which is set to true when a COMP_SHORT_TX event is received and the URB >>> length >>> updated at that stage. >> >> >>> This fixes a bug which affected the HSO plugin, which relies on URBs with >>> urb->actual_length == 0 to halt re-submitting the RX URB in the control >>> endpoint. >> >> >>> Cc: <stable@xxxxxxxxxxxxxxx> >>> Signed-off-by: Aleksander Morgado <aleksander@xxxxxxxxxxxxx> >>> Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> >> >> >> [...] >> >>> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h >>> index 3b97f05..d066393 100644 >>> --- a/drivers/usb/host/xhci.h >>> +++ b/drivers/usb/host/xhci.h >>> @@ -1,3 +1,4 @@ >>> + >>> /* >>> * xHCI host controller driver >>> * >> >> >> Hm, I thought you've dropped this new line... >> > > Ouch; sorry for that. How do I fix that now? Submit another patch just > removing it? Or resubmit a v6 of the patch? I think Greg already > cherry-picked it to his branch. > I can clean up the extra empty line later in some generic code cleanup patch. Don't worry about it -Mathias -- 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
