David, On Mon, 12 Nov 2007, David P. Reed wrote:
> From: David P. Reed > > Fix a typo in ntp.c that has caused updating of the persistent (RTC) clock > when synced to NTP to behave erratically. Good catch. > Signed-off-by: David P. Reed Whitespace damaged as well. Please fix and resend > --- > When debugging a freeze that arises on my AMD64 machines when I run the > ntpd service, I added a number of printk's to monitor the sync_cmos_clock > procedure. I discovered that it was not syncing to cmos RTC every 11 minutes > as documented, but instead would keep trying every second for hours at a time. > The reason turned out to be a typo in sync_cmos_clock, where it attempts to > ensure that update_persistent_clock is called very close to 500 msec. after a > 1 second boundary (required by the PC RTC's spec). That typo referred to > "xtime" in one spot, rather than "now", which is derived from "xtime" but not > equal to it. This makes the test erratic, creating a "coin-flip" that decides > when update_persistent_clock is called - when it is called, which is rarely, > it may be at any time during the one second period, rather than close to 500 > msec, so the value written is needlessly incorrect, too. Please put the explanation into the changelog. > The patch works in 2.6.24rc2, but it should also work in 2.6.23. Yup > @@ -205,7 +206,10 @@ static void sync_cmos_clock(unsigned lon > return; > > getnstimeofday(&now); > - if (abs(xtime.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) Can we just s/xtime/now/ ? There is no value in an extra variable. Thanks, tglx - 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/