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Commit c44b2250 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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UHCI: implement new semantics for URB_ISO_ASAP 



This patch (as1613) updates the isochronous scheduling in uhci-hcd to
match the new semantics for URB_ISO_ASAP.  The amount of code
alteration is smaller than it looks because of a change in the
indentation level.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4005ad43

drivers/usb/host/uhci-q.c

+36 −37
Original line number Original line Diff line number Diff line
@@ -1256,7 +1256,8 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, 
		struct uhci_qh *qh)

		struct uhci_qh *qh)

{

{

	struct uhci_td *td = NULL;	/* Since urb->number_of_packets > 0 */

	struct uhci_td *td = NULL;	/* Since urb->number_of_packets > 0 */

	int i, frame;

	int i;

	unsigned frame, next;

	unsigned long destination, status;

	unsigned long destination, status;

	struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv;

	struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv;
@@ -1265,37 +1266,29 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, 
			urb->number_of_packets >= UHCI_NUMFRAMES)

			urb->number_of_packets >= UHCI_NUMFRAMES)

		return -EFBIG;

		return -EFBIG;





	uhci_get_current_frame_number(uhci);



	/* Check the period and figure out the starting frame number */

	/* Check the period and figure out the starting frame number */

	if (!qh->bandwidth_reserved) {

	if (!qh->bandwidth_reserved) {

		qh->period = urb->interval;

		qh->period = urb->interval;

		if (urb->transfer_flags & URB_ISO_ASAP) {

		qh->phase = -1;		/* Find the best phase */

		qh->phase = -1;		/* Find the best phase */

		i = uhci_check_bandwidth(uhci, qh);

		i = uhci_check_bandwidth(uhci, qh);

		if (i)

		if (i)

			return i;

			return i;





		/* Allow a little time to allocate the TDs */

		/* Allow a little time to allocate the TDs */

			uhci_get_current_frame_number(uhci);

		next = uhci->frame_number + 10;

			frame = uhci->frame_number + 10;

		frame = qh->phase;





			/* Move forward to the first frame having the

		/* Round up to the first available slot */

			 * correct phase */

		frame += (next - frame + qh->period - 1) & -qh->period;

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

					(qh->period - 1));

		} else {

			i = urb->start_frame - uhci->last_iso_frame;

			if (i <= 0 || i >= UHCI_NUMFRAMES)

				return -EINVAL;

			qh->phase = urb->start_frame & (qh->period - 1);

			i = uhci_check_bandwidth(uhci, qh);

			if (i)

				return i;

		}





	} else if (qh->period != urb->interval) {

	} else if (qh->period != urb->interval) {

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

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





	} else {

	} else {

		next = uhci->frame_number + 2;



		/* Find the next unused frame */

		/* Find the next unused frame */

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

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

			frame = qh->iso_frame;

			frame = qh->iso_frame;
@@ -1308,25 +1301,31 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, 
					lurb->number_of_packets *

					lurb->number_of_packets *

					lurb->interval;

					lurb->interval;

		}

		}

		if (urb->transfer_flags & URB_ISO_ASAP) {



			/* Skip some frames if necessary to insure

		/* Fell behind? */

			 * the start frame is in the future.

		if (uhci_frame_before_eq(frame, next)) {



			/* USB_ISO_ASAP: Round up to the first available slot */

			if (urb->transfer_flags & URB_ISO_ASAP)

				frame += (next - frame + qh->period - 1) &

						-qh->period;



			/*

			 * Not ASAP: Use the next slot in the stream.  If

			 * the entire URB falls before the threshold, fail.

			 */

			 */

			uhci_get_current_frame_number(uhci);

			else if (!uhci_frame_before_eq(next,

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

					frame + (urb->number_of_packets - 1) *

				frame = uhci->frame_number + 1;

						qh->period))

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

				return -EXDEV;

					(qh->period - 1));

		}

		}

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

		urb->start_frame = frame;

	}

	}





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

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

	if (uhci_frame_before_eq(uhci->last_iso_frame + UHCI_NUMFRAMES,

	if (uhci_frame_before_eq(uhci->last_iso_frame + UHCI_NUMFRAMES,

			urb->start_frame + urb->number_of_packets *

			frame + urb->number_of_packets * urb->interval))

				urb->interval))

		return -EFBIG;

		return -EFBIG;

	urb->start_frame = frame;





	status = TD_CTRL_ACTIVE | TD_CTRL_IOS;

	status = TD_CTRL_ACTIVE | TD_CTRL_IOS;

	destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);

	destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);