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-q.c b/drivers/usb/host/ehci-q.c
index 57a8479..00ad9ce 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -299,7 +299,6 @@
static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
-static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
/*
@@ -555,14 +554,9 @@
* That should be rare for interrupt transfers,
* except maybe high bandwidth ...
*/
- if ((cpu_to_hc32(ehci, QH_SMASK)
- & hw->hw_info2) != 0) {
- intr_deschedule (ehci, qh);
- (void) qh_schedule (ehci, qh);
- } else {
- /* Tell the caller to start an unlink */
- qh->needs_rescan = 1;
- }
+
+ /* Tell the caller to start an unlink */
+ qh->needs_rescan = 1;
break;
/* otherwise, unlink already started */
}