Hello.
On 01-10-2012 16:32, Alan Stern wrote:
This patch (as1614) updates the isochronous scheduling in ohci-hcd to
match the new semantics for URB_ISO_ASAP. Testing revealed a hardware
bug in the way my OHCI controller handles expired isochronous TDs;
consequently the patch tries hard to avoid creating them (unlike the
ehci-hcd and uhci-hcd drivers).
Signed-off-by: Alan Stern<stern@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/ohci-hcd.c | 36 ++++++++++++++++++++++++++++++++----
drivers/usb/host/ohci-q.c | 4 ++--
2 files changed, 34 insertions(+), 6 deletions(-)
Index: usb-3.6/drivers/usb/host/ohci-hcd.c
===================================================================
--- usb-3.6.orig/drivers/usb/host/ohci-hcd.c
+++ usb-3.6/drivers/usb/host/ohci-hcd.c
@@ -231,13 +231,41 @@ static int ohci_urb_enqueue (
frame&= ~(ed->interval - 1);
frame |= ed->branch;
urb->start_frame = frame;
+ }
+ } else if (ed->type == PIPE_ISOCHRONOUS) {
+ u16 next = ohci_frame_no(ohci) + 2;
+ u16 frame = ed->last_iso + ed->interval;
+
+ /* Behind the scheduling threshold? */
+ if (unlikely(tick_before(frame, next))) {
+
+ /* USB_ISO_ASAP: Round up to the first available slot */
+ if (urb->transfer_flags& URB_ISO_ASAP)
+ frame += (next - frame + ed->interval - 1)&
+ -ed->interval;
+
+ /*
+ * Not ASAP: Use the next slot in the stream. If
+ * the entire URB falls before the threshold, fail.
+ */
+ else if (tick_before(frame + ed->interval *
+ (urb->number_of_packets - 1), next)) {
Erm, both arms of *if* should have {}, according to CodingStyle...
+ retval = -EXDEV;
+ usb_hcd_unlink_urb_from_ep(hcd, urb);
+ goto fail;
+ }
WBR, Sergei
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