diff options
Diffstat (limited to 'drivers/usb/host/uhci-q.c')
| -rw-r--r-- | drivers/usb/host/uhci-q.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c index e5d60d5..60379b1 100644 --- a/drivers/usb/host/uhci-q.c +++ b/drivers/usb/host/uhci-q.c @@ -1271,7 +1271,8 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, } else if (qh->period != urb->interval) { return -EINVAL; /* Can't change the period */ - } else { /* Pick up where the last URB leaves off */ + } else { + /* Find the next unused frame */ if (list_empty(&qh->queue)) { frame = qh->iso_frame; } else { @@ -1283,10 +1284,18 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, lurb->number_of_packets * lurb->interval; } - if (urb->transfer_flags & URB_ISO_ASAP) - urb->start_frame = frame; - else if (urb->start_frame != frame) - return -EINVAL; + if (urb->transfer_flags & URB_ISO_ASAP) { + /* Skip some frames if necessary to insure + * the start frame is in the future. + */ + uhci_get_current_frame_number(uhci); + if (uhci_frame_before_eq(frame, uhci->frame_number)) { + frame = uhci->frame_number + 1; + frame += ((qh->phase - frame) & + (qh->period - 1)); + } + } /* Otherwise pick up where the last URB leaves off */ + urb->start_frame = frame; } /* Make sure we won't have to go too far into the future */ |