diff options
| -rw-r--r-- | drivers/usb/host/ehci-sched.c | 70 | ||||
| -rw-r--r-- | drivers/usb/host/ehci.h | 2 |
2 files changed, 33 insertions, 39 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 7cf3da7babf0..7eb242f27c00 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1361,7 +1361,7 @@ sitd_slot_ok ( * given EHCI_TUNE_FLS and the slop). Or, write a smarter scheduler! */ -#define SCHEDULE_SLOP 80 /* microframes */ +#define SCHEDULING_DELAY 40 /* microframes */ static int iso_stream_schedule ( @@ -1370,7 +1370,7 @@ iso_stream_schedule ( struct ehci_iso_stream *stream ) { - u32 now, next, start, period, span; + u32 now, base, next, start, period, span; int status; unsigned mod = ehci->periodic_size << 3; struct ehci_iso_sched *sched = urb->hcpriv; @@ -1382,12 +1382,6 @@ iso_stream_schedule ( span <<= 3; } - if (span > mod - SCHEDULE_SLOP) { - ehci_dbg (ehci, "iso request %p too long\n", urb); - status = -EFBIG; - goto fail; - } - now = ehci_read_frame_index(ehci) & (mod - 1); /* Typical case: reuse current schedule, stream is still active. @@ -1396,7 +1390,6 @@ iso_stream_schedule ( * slot in the schedule, implicitly assuming URB_ISO_ASAP. */ if (likely (!list_empty (&stream->td_list))) { - u32 excess; /* For high speed devices, allow scheduling within the * isochronous scheduling threshold. For full speed devices @@ -1408,36 +1401,41 @@ iso_stream_schedule ( else next = now; - /* Fell behind (by up to twice the slop amount)? - * We decide based on the time of the last currently-scheduled - * slot, not the time of the next available slot. + /* + * Use ehci->last_iso_frame as the base. There can't be any + * TDs scheduled for earlier than that. */ - excess = (stream->next_uframe - period - next) & (mod - 1); - if (excess >= mod - 2 * SCHEDULE_SLOP) - start = next + excess - mod + period * - DIV_ROUND_UP(mod - excess, period); - else - start = next + excess + period; - if (start - now >= mod) { - ehci_dbg(ehci, "request %p would overflow (%d+%d >= %d)\n", - urb, start - now - period, period, - mod); - status = -EFBIG; + base = ehci->last_iso_frame << 3; + next = (next - base) & (mod - 1); + start = (stream->next_uframe - base) & (mod - 1); + + /* Is the schedule already full? */ + if (unlikely(start < period)) { + ehci_dbg(ehci, "iso sched full %p (%u-%u < %u mod %u)\n", + urb, stream->next_uframe, base, + period, mod); + status = -ENOSPC; goto fail; } + + /* Behind the scheduling threshold? Assume URB_ISO_ASAP. */ + if (unlikely(start < next)) + start += period * DIV_ROUND_UP(next - start, period); + + start += base; } /* need to schedule; when's the next (u)frame we could start? * this is bigger than ehci->i_thresh allows; scheduling itself - * isn't free, the slop should handle reasonably slow cpus. it + * isn't free, the delay should handle reasonably slow cpus. it * can also help high bandwidth if the dma and irq loads don't * jump until after the queue is primed. */ else { int done = 0; - start = SCHEDULE_SLOP + (now & ~0x07); - /* NOTE: assumes URB_ISO_ASAP, to limit complexity/bugs */ + base = now & ~0x07; + start = base + SCHEDULING_DELAY; /* find a uframe slot with enough bandwidth. * Early uframes are more precious because full-speed @@ -1464,19 +1462,16 @@ iso_stream_schedule ( /* no room in the schedule */ if (!done) { - ehci_dbg(ehci, "iso resched full %p (now %d max %d)\n", - urb, now, now + mod); + ehci_dbg(ehci, "iso sched full %p", urb); status = -ENOSPC; goto fail; } } /* Tried to schedule too far into the future? */ - if (unlikely(start - now + span - period - >= mod - 2 * SCHEDULE_SLOP)) { - ehci_dbg(ehci, "request %p would overflow (%d+%d >= %d)\n", - urb, start - now, span - period, - mod - 2 * SCHEDULE_SLOP); + if (unlikely(start - base + span - period >= mod)) { + ehci_dbg(ehci, "request %p would overflow (%u+%u >= %u)\n", + urb, start - base, span - period, mod); status = -EFBIG; goto fail; } @@ -1490,7 +1485,7 @@ iso_stream_schedule ( /* Make sure scan_isoc() sees these */ if (ehci->isoc_count == 0) - ehci->next_frame = now >> 3; + ehci->last_iso_frame = now >> 3; return 0; fail: @@ -2220,16 +2215,16 @@ static void scan_isoc(struct ehci_hcd *ehci) now_frame = (uf >> 3) & fmask; live = true; } else { - now_frame = (ehci->next_frame - 1) & fmask; + now_frame = (ehci->last_iso_frame - 1) & fmask; live = false; } ehci->now_frame = now_frame; - frame = ehci->next_frame; for (;;) { union ehci_shadow q, *q_p; __hc32 type, *hw_p; + frame = ehci->last_iso_frame; restart: /* scan each element in frame's queue for completions */ q_p = &ehci->pshadow [frame]; @@ -2334,7 +2329,6 @@ restart: /* Stop when we have reached the current frame */ if (frame == now_frame) break; - frame = (frame + 1) & fmask; + ehci->last_iso_frame = (frame + 1) & fmask; } - ehci->next_frame = now_frame; } diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h index da07d98f7d1d..0564a63f5eb3 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -143,7 +143,7 @@ struct ehci_hcd { /* one per controller */ struct ehci_qh *intr_unlink_last; unsigned intr_unlink_cycle; unsigned now_frame; /* frame from HC hardware */ - unsigned next_frame; /* scan periodic, start here */ + unsigned last_iso_frame; /* last frame scanned for iso */ unsigned intr_count; /* intr activity count */ unsigned isoc_count; /* isoc activity count */ unsigned periodic_count; /* periodic activity count */ |