From: Martin Burnicki <burnicki@ntp.org>
Date: Fri, 20 Mar 2015 12:03:38 +0000 (+0100)
Subject: [Bug 2790] If ntpd sets the Windows MM timer highest resolution then pause
X-Git-Tag: NTP_4_3_10~3^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3a5ad1af2b9024167de70a3b81105a53902a2d9e;p=thirdparty%2Fntp.git

[Bug 2790] If ntpd sets the Windows MM timer highest resolution then pause
briefly before measuring system clock precision to yield correct results.

bk: 550c0c9aTvwsm95o3ZFcNueZPEsbbQ
---

diff --git a/ChangeLog b/ChangeLog
index 04fb22a9d..3012da385 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 ---
-
+* [Bug 2790] If ntpd sets the Windows MM timer highest resolution
+  pause briefly before measuring system clock precision to yield
+  correct results.
 * [Bug 2728] See if C99-style structure initialization works.
 * [Bug 2747] Upgrade libevent to 2.1.5-beta.
 * [Bug 2749] ntp/lib/NTP/Util.pm needs update for ntpq -w, IPv6, .POOL. .
diff --git a/ports/winnt/ntpd/nt_clockstuff.c b/ports/winnt/ntpd/nt_clockstuff.c
index 907c9f4ee..dc2f150b7 100644
--- a/ports/winnt/ntpd/nt_clockstuff.c
+++ b/ports/winnt/ntpd/nt_clockstuff.c
@@ -824,6 +824,10 @@ init_winnt_time(void)
 			
 			msyslog(LOG_INFO, "MM timer resolution: %u..%u msec, set to %u msec",
 				tc.wPeriodMin, tc.wPeriodMax, wTimerRes );
+
+			/* Pause briefly before measuring the clock precision, see [Bug 2790] */
+			Sleep( 33 );
+
 		} else {
 			msyslog(LOG_ERR, "Multimedia timer unavailable");
 		}