On Fri, 10 Jun 2016, Alan Stern wrote:
> On Fri, 10 Jun 2016, Sean M. Pappalardo wrote:
>
> >
> >
> > On 06/10/2016 11:06 AM, Alan Stern wrote:
> > > Have you tried plugging the audio
> > > devices into a USB-2 hub and plugging the hub into bus 2?
> >
> > That works!! (I forgot, my monitor has a built-in 2-port USB2.0 hub.)
>
> Great!
>
> > So what's going on here? How does adding another hub layer help??
>
> I have no clue. The idea was suggested by the fact that your devices
> worked okay when plugged into the docking station, which has its own
> hub.
Actually, after reviewing the data files you sent I did have a thought.
Can you try out the patch below and see if it makes any difference?
Alan Stern
Index: usb-4.x/drivers/usb/host/ehci-sched.c
===================================================================
--- usb-4.x.orig/drivers/usb/host/ehci-sched.c
+++ usb-4.x/drivers/usb/host/ehci-sched.c
@@ -861,7 +861,7 @@ done:
static int qh_schedule(struct ehci_hcd *ehci, struct ehci_qh *qh)
{
int status = 0;
- unsigned uframe;
+ int uframe;
unsigned c_mask;
struct ehci_qh_hw *hw = qh->hw;
struct ehci_tt *tt;
@@ -893,7 +893,7 @@ static int qh_schedule(struct ehci_hcd *
for (i = qh->ps.bw_period; i > 0; --i) {
frame = ++ehci->random_frame & (qh->ps.bw_period - 1);
- for (uframe = 0; uframe < 8; uframe++) {
+ for (uframe = 7; uframe >= 0; uframe--) {
status = check_intr_schedule(ehci,
frame, uframe, qh, &c_mask, tt);
if (status == 0)
--
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