diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2013-10-11 11:28:02 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-10-11 16:37:45 -0700 |
| commit | 63fb3a280061c5a1d9190015e5a074213f9d23c0 (patch) | |
| tree | d19fa5a572dfc898651194b3ab50848035cc423a /include/linux/usb | |
| parent | 6ec4147e7bdbde168f5bce30de5984aa4f971b22 (diff) | |
USB: NS_TO_US should round up
Host controller drivers use the NS_TO_US macro to convert transaction
times, which are computed in nanoseconds, to microseconds for
scheduling. Periodic scheduling requires worst-case estimates, but
the macro does its conversion using round-to-nearest. This patch
changes it to use round-up, giving a correct worst-case value.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/usb')
| -rw-r--r-- | include/linux/usb/hcd.h | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h index fc64b6825f5..dbe3cd19ffd 100644 --- a/include/linux/usb/hcd.h +++ b/include/linux/usb/hcd.h @@ -564,9 +564,8 @@ extern void usb_ep0_reinit(struct usb_device *); * of (7/6 * 8 * bytecount) = 9.33 * bytecount */ /* bytecount = data payload byte count */ -#define NS_TO_US(ns) ((ns + 500L) / 1000L) - /* convert & round nanoseconds to microseconds */ - +#define NS_TO_US(ns) DIV_ROUND_UP(ns, 1000L) + /* convert nanoseconds to microseconds, rounding up */ /* * Full/low speed bandwidth allocation constants/support. |