USB: EHCI: change deschedule logic for interrupt QHs
This patch (as1281) changes the way ehci-hcd deschedules interrupt
QHs, copying the approach used for async QHs. The caller is no longer
responsible for rescheduling the QH if its queue is non-empty; instead
the reschedule is done directly by intr_deschedule(), after calling
qh_completions(). This is exactly the same as how end_unlink_async()
works.
ehci_urb_dequeue() and intr_deschedule() now correctly handle the case
where they are called while another interrupt URB for the same QH is
being given back. This was a surprisingly large blind spot. And
scan_periodic() now respects the new needs_rescan flag.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index d7e85b6..4f89d7f 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -934,8 +934,9 @@
break;
switch (qh->qh_state) {
case QH_STATE_LINKED:
+ case QH_STATE_COMPLETING:
intr_deschedule (ehci, qh);
- /* FALL THROUGH */
+ break;
case QH_STATE_IDLE:
qh_completions (ehci, qh);
break;
@@ -944,23 +945,6 @@
qh, qh->qh_state);
goto done;
}
-
- /* reschedule QH iff another request is queued */
- if (!list_empty (&qh->qtd_list)
- && HC_IS_RUNNING (hcd->state)) {
- rc = qh_schedule(ehci, qh);
-
- /* An error here likely indicates handshake failure
- * or no space left in the schedule. Neither fault
- * should happen often ...
- *
- * FIXME kill the now-dysfunctional queued urbs
- */
- if (rc != 0)
- ehci_err(ehci,
- "can't reschedule qh %p, err %d",
- qh, rc);
- }
break;
case PIPE_ISOCHRONOUS:
@@ -1079,12 +1063,10 @@
* while the QH is active. Unlink it now;
* re-linking will call qh_refresh().
*/
- if (eptype == USB_ENDPOINT_XFER_BULK) {
+ if (eptype == USB_ENDPOINT_XFER_BULK)
unlink_async(ehci, qh);
- } else {
+ else
intr_deschedule(ehci, qh);
- (void) qh_schedule(ehci, qh);
- }
}
}
spin_unlock_irqrestore(&ehci->lock, flags);