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USB: EHCI: improve ehci_endpoint_disable

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The patch does the below improvement:

- think QH_STATE_COMPLETING as unlinking state since all URBs on the
endpoint should be in unlinking or unlinked when doing endpoint_disable()

- add "WARN_ON(!list_empty(&qh->qtd_list));" if qh->qh_state is
QH_STATE_LINKED because there shouldn't be any active transfer in qh

- when qh->qh_state is QH_STATE_LINKED, the QH(async or periodic)
should be in its corresponding list, so the search through the async
list isn't necessary.

- unlink periodic QH to speed up unlinking if the QH is in linked
state

Basically, only the last one is related with this patchset because
the assumption of "periodic qh self-unlinks on empty" isn't true
any more when we introduce unlink-wait for periodic qh.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ming Lei 2013-07-03 22:53:09 +08:00 committed by Greg Kroah-Hartman
parent 85721d4526
commit 35371e4fbc
1 changed files with 6 additions and 10 deletions
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16
drivers/usb/host/ehci-hcd.c
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@ -942,7 +942,7 @@ ehci_endpoint_disable (struct usb_hcd *hcd, struct usb_host_endpoint *ep)
{
struct ehci_hcd *ehci = hcd_to_ehci (hcd);
unsigned long flags;
struct ehci_qh *qh, *tmp;
struct ehci_qh *qh;
/* ASSERT: any requests/urbs are being unlinked */
/* ASSERT: nobody can be submitting urbs for this any more */
@ -972,17 +972,13 @@ rescan:
qh->qh_state = QH_STATE_IDLE;
switch (qh->qh_state) {
case QH_STATE_LINKED:
case QH_STATE_COMPLETING:
for (tmp = ehci->async->qh_next.qh;
tmp && tmp != qh;
tmp = tmp->qh_next.qh)
continue;
/* periodic qh self-unlinks on empty, and a COMPLETING qh
* may already be unlinked.
*/
if (tmp)
WARN_ON(!list_empty(&qh->qtd_list));
if (usb_endpoint_type(&ep->desc) != USB_ENDPOINT_XFER_INT)
start_unlink_async(ehci, qh);
else
start_unlink_intr(ehci, qh);
/* FALL THROUGH */
case QH_STATE_COMPLETING: /* already in unlinking */
case QH_STATE_UNLINK: /* wait for hw to finish? */
case QH_STATE_UNLINK_WAIT:
idle_timeout: