Commit 72675479 authored Sep 28, 2012 by Alan Stern Committed by Greg Kroah-Hartman Oct 22, 2012

EHCI: replace mult/div with bit-mask operation



This patch (as1610) replaces multiplication and divison operations in
ehci-hcd's isochronous scheduling code with a bit-mask operation,
taking advantage of the fact that isochronous periods are always
powers of 2.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 98cae42d

drivers/usb/host/ehci-sched.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1416,7 +1416,7 @@ iso_stream_schedule (

		/* Behind the scheduling threshold? Assume URB_ISO_ASAP. */
		if (unlikely(start < next))
		start += period * DIV_ROUND_UP(next - start, period);
		start += (next - start + period - 1) & (- period);

		start += base;
		}