diff options
| author | Nico Huber <nico.huber@secunet.com> | 2012-11-22 11:14:03 +0100 |
|---|---|---|
| committer | Patrick Georgi <patrick@georgi-clan.de> | 2012-11-23 18:18:59 +0100 |
| commit | af169f4dd515f52e26c4c476c3340a710db69887 (patch) | |
| tree | f1727b8facc20f74827fad6f1a598a5242642b12 | |
| parent | b2db28babe0e64e08b1a754b65dd7e437f8d82a9 (diff) | |
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@secunet.com>
Reviewed-on: http://review.coreboot.org/1902
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Tested-by: build bot (Jenkins)
| -rw-r--r-- | payloads/libpayload/drivers/usb/ehci.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/payloads/libpayload/drivers/usb/ehci.c b/payloads/libpayload/drivers/usb/ehci.c index 4ff137e40b..6a1cfb5791 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); } |