From: cheloha <cheloha@openbsd.org>
Date: Tue, 8 Nov 2022 18:17:51 +0000 (+0000)
Subject: tc_setclock: don't print a warning if tc_windup() rejects inittodr(9) time
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=a6064e195483fbb40ef206fe2294ca6b0d64eda7;p=openbsd

tc_setclock: don't print a warning if tc_windup() rejects inittodr(9) time

During resume, it isn't necessarily a problem if the UTC time we get
from inittodr(9) lags behind the system UTC clock.  In particular, if
the active timecounter's frequency is low enough, tc_delta() might not
overflow across a brief suspend.

Remove the misleading warning message.  The code is behaving as
intended, just not in a way I anticipated when I added the warning
message a few years ago.

Discovered by kettenis@.  Root cause isolated with kettenis@.

Link: https://marc.info/?l=openbsd-tech&m=166790845619897&w=2

ok mlarkin@ kettenis@
---

diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index 3509b8f2bd9..297eccc95de 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_tc.c,v 1.78 2022/09/18 20:47:09 cheloha Exp $ */
+/*	$OpenBSD: kern_tc.c,v 1.79 2022/11/08 18:17:51 cheloha Exp $ */
 
 /*
  * Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
@@ -552,7 +552,6 @@ void
 tc_setclock(const struct timespec *ts)
 {
 	struct bintime new_naptime, old_naptime, uptime, utc;
-	struct timespec tmp;
 	static int first = 1;
 #ifndef SMALL_KERNEL
 	struct bintime elapsed;
@@ -583,12 +582,6 @@ tc_setclock(const struct timespec *ts)
 
 	mtx_leave(&windup_mtx);
 
-	if (bintimecmp(&old_naptime, &new_naptime, ==)) {
-		BINTIME_TO_TIMESPEC(&uptime, &tmp);
-		printf("%s: cannot rewind uptime to %lld.%09ld\n",
-		    __func__, (long long)tmp.tv_sec, tmp.tv_nsec);
-	}
-
 #ifndef SMALL_KERNEL
 	/* convert the bintime to ticks */
 	bintimesub(&new_naptime, &old_naptime, &elapsed);