sleep: doc update for multiple battery, acpi_btp support and freeze/thaw user.slice

diff --git a/man/systemd-sleep.conf.xml b/man/systemd-sleep.conf.xml
index 8b9ddd6e7dd04431f0fc7aa53f9be95f80ed476c..be04f2cdf1e0bad5f2618f41f9fba5cfa0bb7a49 100644 (file)
--- a/man/systemd-sleep.conf.xml
+++ b/man/systemd-sleep.conf.xml
@@ -77,21 +77,28 @@
       <varlistentry>
         <term>suspend-then-hibernate</term>
 
-        <listitem><para>A low power state where the system is initially suspended
-        (the state is stored in RAM) and then hibernated based on battery percentage
-        capacity. If the current battery capacity is higher than 5%, the system goes
-        back to suspend for interval calculated using battery discharge rate per hour.
+        <listitem><para>A low power state where initially user.slice unit is freezed.
+        If the hardware supports low-battery alarms (ACPI _BTP), then the system is
+        first suspended (the state is stored in RAM) and then hibernates if the system
+        is woken up by the hardware via ACPI low-battery signal. Unit user.slice is
+        thawed when system returns from hibernation. If the hardware does not support
+        low-battery alarms (ACPI _BTP), then the system is suspended based on battery's
+        current percentage capacity. If the current battery capacity is higher than 5%, the
+        system suspends for interval calculated using battery discharge rate per hour or
+        <command>HibernateDelaySec=</command>
+        if former is not available.
         Battery discharge rate per hour is stored in a file which is created after
         initial suspend-resume cycle. The value is calculated using battery decreasing
-        charge level a timespan. In case of manual wakeup before RTC alarm, the timespan
-        is the duration for which system was suspended. If the file does not exist or
-        has invalid value, initial suspend duration is set to
-        <command>HibernateDelaySec=</command>.
-        After wakeup via an RTC alarm, the battery discharge rate per hour is again
-        estimated. If the current battery charge level is equal to or less than 5%,
-        the system will be hibernated (the state is then stored on disk) else the
-        system goes back to suspend for the amount of time it would take to fully
-        discharge the battery minus 30 minutes.
+        charge level over a timespan for which system was suspended. For each battery
+        connected to the system, there is a unique entry. After RTC alarm wakeup from
+        suspend, battery discharge rate per hour is again estimated. If the current battery
+        charge level is equal to or less than 5%, the system will be hibernated (the state
+        is then stored on disk) else the system goes back to suspend for the interval
+        calculated using battery discharge rate per hour.
+        In case of manual wakeup, if the battery was discharged while the system was
+        suspended, the battery discharge rate is estimated and stored on the filesystem.
+        In case the system is woken up by the hardware via the ACPI low-battery signal,
+        then it hibernates.
         </para></listitem>
       </varlistentry>