doc: update FAQ

diff --git a/doc/faq.adoc b/doc/faq.adoc
index 0a1ac7177744cf2aea067d138a430a4d9c6bed86..41bf92e18c9b1e2e2f564e668b6e91209378ad88 100644 (file)
--- a/doc/faq.adoc
+++ b/doc/faq.adoc
@@ -148,9 +148,14 @@ network. It's better to use more than one server, three or four is usually
 recommended as the minimum, so `chronyd` can detect servers that serve false
 time and combine measurements from multiple sources.
 
+If you have a network card with hardware timestamping supported on Linux, it
+can be enabled by the *hwtimestamp* directive in the _chrony.conf_ file. It
+should make local receive and transmit timestamps of NTP packets much more
+accurate.
+
 There are also useful options which can be set in the `server` directive, they
-are `minpoll`, `maxpoll`, `polltarget`, `maxdelay`, `maxdelayratio` and
-`maxdelaydevratio`.
+are `minpoll`, `maxpoll`, `polltarget`, `maxdelay`, `maxdelayratio`,
+`maxdelaydevratio`, and `xleave`.
 
 The first three options set the minimum and maximum allowed polling interval,
 and how should be the actual interval adjusted in the specified range. Their
@@ -189,6 +194,16 @@ with local NTP server
 server ntp.local minpoll 2 maxpoll 4 polltarget 30 maxdelaydevratio 2
 ----
 
+If your server supports the interleaved mode, the `xleave` option should be
+added to the `server` directive in order to receive server's more accurate
+hardware or kernel transmit timestamps. When combined with local hardware
+timestamping, a sub-microsecond accuracy may be possible. An example could be
+
+----
+server ntp.local minpoll 2 maxpoll 2 xleave
+hwtimestamp eth0
+----
+
 === What happened to the `commandkey` and `generatecommandkey` directives?
 
 They were removed in version 2.2. Authentication is no longer supported in the
@@ -376,7 +391,8 @@ to serve time to clients in the network which support the broadcast client mode
 
 === Can `chronyd` keep the system clock a fixed offset away from real time?
 
-This is not possible as the program currently stands.
+Yes. Starting from version 3.0, an offset can be specified by the `offset`
+option for all time sources in the _chrony.conf_ file.
 
 === What happens if the network connection is dropped without using ``chronyc``'s `offline` command first?