ChangeSet 1.1305.7.5, 2003/06/16 12:01:45-07:00, [EMAIL PROTECTED]
[PATCH] USB: ehci, fix qh re-activation problem
This resolves a problem that appears when relinking
a bulk or control QH that has a partially completed
multi-packet qTD. Some I/O could be repeated.
Such cases can happen when an empty QH starts to unlink,
but gets re-activated (by queueing the multi-packet qTD)
before the HC saw the unlink. It's rarely an issue with
control traffic (transfers are so small) or when bulk
queues are active (the QH won't empty).
drivers/usb/host/ehci-hcd.c | 2 +-
drivers/usb/host/ehci-q.c | 16 +++++++++++-----
2 files changed, 12 insertions(+), 6 deletions(-)
diff -Nru a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
--- a/drivers/usb/host/ehci-hcd.c Wed Jun 18 11:15:55 2003
+++ b/drivers/usb/host/ehci-hcd.c Wed Jun 18 11:15:55 2003
@@ -91,7 +91,7 @@
* 2001-June Works with usb-storage and NEC EHCI on 2.4
*/
-#define DRIVER_VERSION "2003-Jun-12"
+#define DRIVER_VERSION "2003-Jun-13"
#define DRIVER_AUTHOR "David Brownell"
#define DRIVER_DESC "USB 2.0 'Enhanced' Host Controller (EHCI) Driver"
diff -Nru a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
--- a/drivers/usb/host/ehci-q.c Wed Jun 18 11:15:55 2003
+++ b/drivers/usb/host/ehci-q.c Wed Jun 18 11:15:55 2003
@@ -360,11 +360,17 @@
if (unlikely (stopped != 0)
/* some EHCI 0.95 impls will overlay dummy qtds */
|| qh->hw_qtd_next == EHCI_LIST_END) {
- qh_update (ehci, qh,
- list_empty (&qh->qtd_list)
- ? qh->dummy
- : list_entry (qh->qtd_list.next,
- struct ehci_qtd, qtd_list));
+ if (list_empty (&qh->qtd_list))
+ end = qh->dummy;
+ else {
+ end = list_entry (qh->qtd_list.next,
+ struct ehci_qtd, qtd_list);
+ /* first qtd may already be partially processed */
+ if (cpu_to_le32 (end->qtd_dma) == qh->hw_current)
+ end = 0;
+ }
+ if (end)
+ qh_update (ehci, qh, end);
}
return count;
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