Commit 7898ffc5 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

USB: fix scheduling of Iso URBs in uhci-hcd 



This patch (as1003) changes uhci-hcd to treat the URB_ISO_ASAP flag
the same as other host controller drivers, namely, to schedule an Iso
URB for the first available time slot that hasn't already expired.
URBs in which the flag isn't set will be scheduled for the first slot
following the last URB, even if it has expired.

This fixes a problem reported by Martin Bachem.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 6ce073bd

drivers/usb/host/uhci-q.c

+14 −5
Original line number Diff line number Diff line
@@ -1271,7 +1271,8 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, 
	} else if (qh->period != urb->interval) {

		return -EINVAL;		/* Can't change the period */



	} else {	/* Pick up where the last URB leaves off */

	} else {

		/* Find the next unused frame */

		if (list_empty(&qh->queue)) {

			frame = qh->iso_frame;

		} else {
@@ -1283,10 +1284,18 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, 
					lurb->number_of_packets *

					lurb->interval;

		}

		if (urb->transfer_flags & URB_ISO_ASAP)

		if (urb->transfer_flags & URB_ISO_ASAP) {

			/* Skip some frames if necessary to insure

			 * the start frame is in the future.

			 */

			uhci_get_current_frame_number(uhci);

			if (uhci_frame_before_eq(frame, uhci->frame_number)) {

				frame = uhci->frame_number + 1;

				frame += ((qh->phase - frame) &

					(qh->period - 1));

			}

		}	/* Otherwise pick up where the last URB leaves off */

		urb->start_frame = frame;

		else if (urb->start_frame != frame)

			return -EINVAL;

	}



	/* Make sure we won't have to go too far into the future */

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