diff options
| -rw-r--r-- | drivers/usb/host/ehci-sched.c | 44 |
1 files changed, 23 insertions, 21 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index b5f957d322e..7ce5c2a2fe3 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1491,8 +1491,6 @@ sitd_slot_ok ( * given EHCI_TUNE_FLS and the slop). Or, write a smarter scheduler! */ -#define SCHEDULING_DELAY 40 /* microframes */ - static int iso_stream_schedule ( struct ehci_hcd *ehci, @@ -1506,27 +1504,13 @@ iso_stream_schedule ( unsigned mod = ehci->periodic_size << 3; struct ehci_iso_sched *sched = urb->hcpriv; bool empty = list_empty(&stream->td_list); + bool new_stream = false; period = stream->uperiod; span = sched->span; if (!stream->highspeed) span <<= 3; - now = ehci_read_frame_index(ehci) & (mod - 1); - - /* Take the isochronous scheduling threshold into account */ - if (ehci->i_thresh) - next = now + ehci->i_thresh; /* uframe cache */ - else - next = (now + 2 + 7) & ~0x07; /* full frame cache */ - - /* - * Use ehci->last_iso_frame as the base. There can't be any - * TDs scheduled for earlier than that. - */ - base = ehci->last_iso_frame << 3; - next = (next - base) & (mod - 1); - /* Start a new isochronous stream? */ if (unlikely(empty && !hcd_periodic_completion_in_progress( ehci_to_hcd(ehci), urb->ep))) { @@ -1542,7 +1526,7 @@ iso_stream_schedule ( } compute_tt_budget(ehci->tt_budget, tt); - start = (now & ~0x07) + SCHEDULING_DELAY; + start = ((-(++ehci->random_frame)) << 3) & (period - 1); /* find a uframe slot with enough bandwidth. * Early uframes are more precious because full-speed @@ -1585,17 +1569,35 @@ iso_stream_schedule ( start = (stream->ps.phase << 3) + stream->ps.phase_uf; } - start = (start - base) & (mod - 1); - goto use_start; + stream->next_uframe = start; + new_stream = true; } + now = ehci_read_frame_index(ehci) & (mod - 1); + + /* Take the isochronous scheduling threshold into account */ + if (ehci->i_thresh) + next = now + ehci->i_thresh; /* uframe cache */ + else + next = (now + 2 + 7) & ~0x07; /* full frame cache */ + + /* + * Use ehci->last_iso_frame as the base. There can't be any + * TDs scheduled for earlier than that. + */ + base = ehci->last_iso_frame << 3; + next = (next - base) & (mod - 1); + start = (stream->next_uframe - base) & (mod - 1); + + if (unlikely(new_stream)) + goto do_ASAP; + /* * Typical case: reuse current schedule, stream may still be active. * Hopefully there are no gaps from the host falling behind * (irq delays etc). If there are, the behavior depends on * whether URB_ISO_ASAP is set. */ - start = (stream->next_uframe - base) & (mod - 1); now2 = (now - base) & (mod - 1); /* Is the schedule already full? */ |