[coreboot] New patch to review for coreboot: 7f59b31 libpayload: ehci: Prevent some race conditions
Nico Huber (nico.huber@secunet.com)
gerrit at coreboot.org
Fri Nov 23 15:01:02 CET 2012
Nico Huber (nico.huber at secunet.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/1902
-gerrit
commit 7f59b31c4efaadebd2897b302c381b80f7925cab
Author: Nico Huber <nico.huber at secunet.com>
Date: Thu Nov 22 11:14:03 2012 +0100
libpayload: ehci: Prevent some race conditions
Prevent race conditions, when an interrupt-queue underrun occurred and
the controller is currently working on our queue head or a transfer is
still in progress.
Change-Id: Ia14f80a08071306ee5d1349780be081bfacb206a
Signed-off-by: Nico Huber <nico.huber at secunet.com>
---
payloads/libpayload/drivers/usb/ehci.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/payloads/libpayload/drivers/usb/ehci.c b/payloads/libpayload/drivers/usb/ehci.c
index 4ff137e..6a1cfb5 100644
--- a/payloads/libpayload/drivers/usb/ehci.c
+++ b/payloads/libpayload/drivers/usb/ehci.c
@@ -626,8 +626,14 @@ static u8 *ehci_poll_intr_queue(void *const queue)
intrq->head = intrq->head->next;
}
/* reset queue if we fully processed it after underrun */
- else if (intrq->qh.td.next_qtd & QTD_TERMINATE) {
+ else if ((intrq->qh.td.next_qtd & QTD_TERMINATE) &&
+ /* to prevent race conditions:
+ not our head and not active */
+ (intrq->qh.current_td_ptr !=
+ virt_to_phys(&intrq->head->td)) &&
+ !(intrq->qh.td.token & QTD_ACTIVE)) {
usb_debug("resetting underrun ehci interrupt queue.\n");
+ intrq->qh.current_td_ptr = 0;
memset((void *)&intrq->qh.td, 0, sizeof(intrq->qh.td));
intrq->qh.td.next_qtd = virt_to_phys(&intrq->head->td);
}
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