The old microframe scheduler was terribly hard to follow and (it seemed to me) that it had some bugs in it.
Let's re-write it in a simpler, easier-to-read way. Hopefully this will work better. Note: no known problems are fixed by this patch, and in fact I can see very little impact of the microframe scheduler overall. Signed-off-by: Douglas Anderson <[email protected]> --- drivers/usb/dwc2/hcd_queue.c | 72 ++++++++++++++++++++------------------------ 1 file changed, 32 insertions(+), 40 deletions(-) diff --git a/drivers/usb/dwc2/hcd_queue.c b/drivers/usb/dwc2/hcd_queue.c index 7d8d06cfe3c1..d6c24decee08 100644 --- a/drivers/usb/dwc2/hcd_queue.c +++ b/drivers/usb/dwc2/hcd_queue.c @@ -359,57 +359,49 @@ static int dwc2_find_single_uframe(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) */ static int dwc2_find_multi_uframe(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) { - unsigned short utime = qh->usecs; - unsigned short xtime; - int t_left; + int utime; int i; int j; - int k; for (i = 0; i < 8; i++) { if (hsotg->frame_usecs[i] <= 0) continue; - /* - * we need n consecutive slots so use j as a start slot - * j plus j+1 must be enough time (for now) - */ - xtime = hsotg->frame_usecs[i]; - for (j = i + 1; j < 8; j++) { + for (utime = qh->usecs, j = i; utime > 0 && j < 8; j++) { + /* Give the available time from this uframe */ + utime -= hsotg->frame_usecs[j]; + /* - * if we add this frame remaining time to xtime we may - * be OK, if not we need to test j for a complete frame + * Except for first frame, we can't continue past this + * frame if it wasn't full, so bail now. We might still + * be successful the above subtract made utime <= 0. */ - if (xtime + hsotg->frame_usecs[j] < utime) { - if (hsotg->frame_usecs[j] < - max_uframe_usecs[j]) - continue; - } - if (xtime >= utime) { - t_left = utime; - for (k = i; k < 8; k++) { - t_left -= hsotg->frame_usecs[k]; - if (t_left <= 0) { - qh->frame_usecs[k] += - hsotg->frame_usecs[k] - + t_left; - hsotg->frame_usecs[k] = -t_left; - return i; - } else { - qh->frame_usecs[k] += - hsotg->frame_usecs[k]; - hsotg->frame_usecs[k] = 0; - } - } - } - /* add the frame time to x time */ - xtime += hsotg->frame_usecs[j]; - /* we must have a fully available next frame or break */ - if (xtime < utime && - hsotg->frame_usecs[j] == max_uframe_usecs[j]) - continue; + if ((i != j) && + (hsotg->frame_usecs[j] < max_uframe_usecs[j])) + break; + } + + /* If utime > 0 after above loop, try a different start (i) */ + if (utime > 0) + continue; + + dev_dbg(hsotg->dev, "Assigned %d us starting at i=%d + %d us\n", + qh->usecs, i, + max_uframe_usecs[i] - hsotg->frame_usecs[i]); + + /* We've got success, so allocate */ + for (utime = qh->usecs, j = i; utime > 0 && j < 8; j++) { + qh->frame_usecs[i] = min_t(u16, utime, + hsotg->frame_usecs[j]); + utime -= qh->frame_usecs[i]; + hsotg->frame_usecs[j] -= qh->frame_usecs[i]; } + + return i; } + + dev_dbg(hsotg->dev, "Failed to assign %d us\n", qh->usecs); + return -ENOSPC; } -- 2.6.0.rc2.230.g3dd15c0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
