hwclock: add notes about default behavior changes

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/hwclock.8.in b/sys-utils/hwclock.8.in
index 5df95e761dfcc48fda0255beba2959fd4f3df308..3c021bfe03d3cc9781d71582b29592335f4190e8 100644 (file)
--- a/sys-utils/hwclock.8.in
+++ b/sys-utils/hwclock.8.in
@@ -19,6 +19,19 @@ periodically to add or subtract time from the Hardware Clock to
 compensate for systematic drift (where the clock consistently loses or
 gains time at a certain rate when left to run).
 
+Since v2.26
+.B hwclock
+does not update Hardware Clock's drift factor in @ADJTIME_PATH@ by default.
+It's necessary to use \fB\-\-update-drift\fR with \fB\-\-set\fR or
+\fB\-\-systohc\fR to force drift factor update.
+
+Since v2.26
+.B hwclock
+automatically compensates Hardware Clock to account for systematic drift before
+using it to set the System Clock by \fB\-\-hctosys\fR. It means that
+\fB\-\-adjust\fR is no more necessary during boot. This functionality makes
+hwclock usable early in boot process when the root filesystem is read-only.
+
 .SH FUNCTIONS
 You need exactly one of the following options to tell
 .B hwclock