rtcwake: add note about HW and sleep to the man page

Addresses: https://github.com/karelzak/util-linux/issues/527
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/rtcwake.8.in b/sys-utils/rtcwake.8.in
index 41bbd85e00e1b5a6b1d703016156a6b40d24a379..b35860113c792e4bdc33dd69448f66c2d218d1e5 100644 (file)
--- a/sys-utils/rtcwake.8.in
+++ b/sys-utils/rtcwake.8.in
@@ -45,6 +45,11 @@ appropriate for such suspend modes.
 .PP
 Note that alarm functionality depends on hardware; not every RTC is able to setup 
 an alarm up to 24 hours in the future.
+.PP
+The suspend setup maybe be interrupted by active hardware; for example wireless USB
+input devices that continue to send events for some fraction of a second after the
+return key is pressed. In this case is better to use sleep command before invoking
+suspend by rtcwake.
 .SH OPTIONS
 .TP
 .BR \-A , " \-\-adjfile " \fIfile