diff options
Diffstat (limited to 'drivers/usb/host/ehci-q.c')
| -rw-r--r-- | drivers/usb/host/ehci-q.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index fd252f0cfb3..7bf2b4eeb9c 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -1170,7 +1170,7 @@ static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh) struct ehci_qh *prev; /* Add to the end of the list of QHs waiting for the next IAAD */ - qh->qh_state = QH_STATE_UNLINK; + qh->qh_state = QH_STATE_UNLINK_WAIT; if (ehci->async_unlink) ehci->async_unlink_last->unlink_next = qh; else @@ -1213,9 +1213,19 @@ static void start_iaa_cycle(struct ehci_hcd *ehci, bool nested) /* Do only the first waiting QH (nVidia bug?) */ qh = ehci->async_unlink; - ehci->async_iaa = qh; - ehci->async_unlink = qh->unlink_next; - qh->unlink_next = NULL; + + /* + * Intel (?) bug: The HC can write back the overlay region + * even after the IAA interrupt occurs. In self-defense, + * always go through two IAA cycles for each QH. + */ + if (qh->qh_state == QH_STATE_UNLINK_WAIT) { + qh->qh_state = QH_STATE_UNLINK; + } else { + ehci->async_iaa = qh; + ehci->async_unlink = qh->unlink_next; + qh->unlink_next = NULL; + } /* Make sure the unlinks are all visible to the hardware */ wmb(); |