PM / sleep: Mention async suspend in PM_TRACE documentation
Document pm_tracing actually affecting suspend in non-trivial way.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/power/s2ram.txt b/Documentation/power/s2ram.txt
index 1bdfa04..4685aee 100644
--- a/Documentation/power/s2ram.txt
+++ b/Documentation/power/s2ram.txt
@@ -69,6 +69,10 @@
hardware during resume operations where a value can be set that will
survive a reboot.
+pm_trace is not compatible with asynchronous suspend, so it turns
+asynchronous suspend off (which may work around timing or
+ordering-sensitive bugs).
+
Consequence is that after a resume (even if it is successful) your system
clock will have a value corresponding to the magic number instead of the
correct date/time! It is therefore advisable to use a program like ntp-date