From db8a187c67e4829e39fe28e25003816b64db80db Mon Sep 17 00:00:00 2001

From: Yu Watanabe <watanabe.yu+github@gmail.com>

Date: Mon, 14 Nov 2022 02:08:05 +0900

Subject: [PATCH] sleep: introduce SuspendEstimationSec=

Before v252, HibernateDelaySec= specifies the maximum timespan that the

system in suspend state, and the system hibernate after the timespan.

However, after 96d662fa4c8cab24da57523c5e49e6ef3967fc13, the setting is

repurposed as the default interval to measure battery charge level and

estimate the battery discharging late. And if the system has enough

battery capacity, then the system will stay in suspend state and not

hibernate even if the time passed. See issue #25269.

To keep the backward compatibility, let's introduce another setting

SuspendEstimationSec= for controlling the interval to measure

battery charge level, and make HibernateDelaySec= work as of v251.

This also drops implementation details from the man page.

Fixes #25269.

(cherry picked from commit 4f58b656d92b09a953b7cffcfd1ee6d5136a57ed)

Resolves: #2151612

---

 man/systemd-sleep.conf.xml | 58 ++++++++++++++++++++------------------

 src/shared/sleep-config.c  | 11 ++++++--

 src/shared/sleep-config.h  |  3 ++

 src/sleep/sleep.c          | 48 ++++++++++++++++++++++---------

 src/sleep/sleep.conf       |  3 +-

 5 files changed, 77 insertions(+), 46 deletions(-)

diff --git a/man/systemd-sleep.conf.xml b/man/systemd-sleep.conf.xml

index be04f2cdf1..79ebef1fef 100644

--- a/man/systemd-sleep.conf.xml

+++ b/man/systemd-sleep.conf.xml

@@ -77,29 +77,16 @@

       <varlistentry>

         <term>suspend-then-hibernate</term>

-        <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 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>

+        <listitem>

+          <para>A low power state where the system is initially suspended (the state is stored in

+          RAM). If the system supports low-battery alarms (ACPI _BTP), then the system will be woken up by

+          the ACPI low-battery signal and hibernated (the state is then stored on disk). Also, if not

+          interrupted within the timespan specified by <varname>HibernateDelaySec=</varname> or the estimated

+          timespan until the system battery charge level goes down to 5%, then the system will be woken up by the

+          RTC alarm and hibernated. The estimated timespan is calculated from the change of the battery

+          capacity level after the time specified by <varname>SuspendEstimationSec=</varname> or when

+          the system is woken up from the suspend.</para>

+        </listitem>

       </varlistentry>

     </variablelist>

@@ -189,13 +176,28 @@

         uses the value of <varname>SuspendState=</varname> when suspending and the value of <varname>HibernateState=</varname> when hibernating.

         </para></listitem>

       </varlistentry>

+

       <varlistentry>

         <term><varname>HibernateDelaySec=</varname></term>

-        <listitem><para>The amount of time the system spends in suspend mode

-        before the RTC alarm wakes the system, before the battery discharge rate

-        can be estimated and used instead to calculate the suspension interval.

-        <citerefentry><refentrytitle>systemd-suspend-then-hibernate.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. Defaults

-        to 2h.</para></listitem>

+

+        <listitem>

+          <para>The amount of time the system spends in suspend mode before the system is

+          automatically put into hibernate mode. Only used by

+          <citerefentry><refentrytitle>systemd-suspend-then-hibernate.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.

+          If the system has a battery, then defaults to the estimated timespan until the system battery charge level goes down to 5%.

+          If the system has no battery, then defaults to 2h.</para>

+        </listitem>

+      </varlistentry>

+

+      <varlistentry>

+        <term><varname>SuspendEstimationSec=</varname></term>

+

+        <listitem>

+          <para>The RTC alarm will wake the system after the specified timespan to measure the system battery

+          capacity level and estimate battery discharging rate, which is used for estimating timespan until the system battery charge

+          level goes down to 5%. Only used by

+          <citerefentry><refentrytitle>systemd-suspend-then-hibernate.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.

+          Defaults to 2h.</para></listitem>

       </varlistentry>

     </variablelist>

   </refsect1>

diff --git a/src/shared/sleep-config.c b/src/shared/sleep-config.c

index 359d293fd0..74653effa2 100644

--- a/src/shared/sleep-config.c

+++ b/src/shared/sleep-config.c

@@ -65,10 +65,14 @@ int parse_sleep_config(SleepConfig **ret_sleep_config) {

         int allow_suspend = -1, allow_hibernate = -1,

             allow_s2h = -1, allow_hybrid_sleep = -1;

-        sc = new0(SleepConfig, 1);

+        sc = new(SleepConfig, 1);

         if (!sc)

                 return log_oom();

+        *sc = (SleepConfig) {

+                .hibernate_delay_usec = USEC_INFINITY,

+        };

+

         const ConfigTableItem items[] = {

                 { "Sleep", "AllowSuspend",              config_parse_tristate, 0, &allow_suspend                  },

                 { "Sleep", "AllowHibernation",          config_parse_tristate, 0, &allow_hibernate                },

@@ -83,6 +87,7 @@ int parse_sleep_config(SleepConfig **ret_sleep_config) {

                 { "Sleep", "HybridSleepState",          config_parse_strv,     0, sc->states + SLEEP_HYBRID_SLEEP },

                 { "Sleep", "HibernateDelaySec",         config_parse_sec,      0, &sc->hibernate_delay_usec       },

+                { "Sleep", "SuspendEstimationSec",      config_parse_sec,      0, &sc->suspend_estimation_usec    },

                 {}

         };

@@ -113,8 +118,8 @@ int parse_sleep_config(SleepConfig **ret_sleep_config) {

                 sc->modes[SLEEP_HYBRID_SLEEP] = strv_new("suspend", "platform", "shutdown");

         if (!sc->states[SLEEP_HYBRID_SLEEP])

                 sc->states[SLEEP_HYBRID_SLEEP] = strv_new("disk");

-        if (sc->hibernate_delay_usec == 0)

-                sc->hibernate_delay_usec = 2 * USEC_PER_HOUR;

+        if (sc->suspend_estimation_usec == 0)

+                sc->suspend_estimation_usec = DEFAULT_SUSPEND_ESTIMATION_USEC;

         /* ensure values set for all required fields */

         if (!sc->states[SLEEP_SUSPEND] || !sc->modes[SLEEP_HIBERNATE]

diff --git a/src/shared/sleep-config.h b/src/shared/sleep-config.h

index 226fab4b9f..480e90c95b 100644

--- a/src/shared/sleep-config.h

+++ b/src/shared/sleep-config.h

@@ -6,6 +6,8 @@

 #include "hashmap.h"

 #include "time-util.h"

+#define DEFAULT_SUSPEND_ESTIMATION_USEC (1 * USEC_PER_HOUR)

+

 typedef enum SleepOperation {

         SLEEP_SUSPEND,

         SLEEP_HIBERNATE,

@@ -20,6 +22,7 @@ typedef struct SleepConfig {

         char **modes[_SLEEP_OPERATION_MAX];

         char **states[_SLEEP_OPERATION_MAX];

         usec_t hibernate_delay_usec;

+        usec_t suspend_estimation_usec;

 } SleepConfig;

 SleepConfig* free_sleep_config(SleepConfig *sc);

diff --git a/src/sleep/sleep.c b/src/sleep/sleep.c

index 039b123dcc..0bbea9e856 100644

--- a/src/sleep/sleep.c

+++ b/src/sleep/sleep.c

@@ -268,10 +268,13 @@ static int execute(

 static int custom_timer_suspend(const SleepConfig *sleep_config) {

         _cleanup_hashmap_free_ Hashmap *last_capacity = NULL, *current_capacity = NULL;

+        usec_t hibernate_timestamp;

         int r;

         assert(sleep_config);

+        hibernate_timestamp = usec_add(now(CLOCK_BOOTTIME), sleep_config->hibernate_delay_usec);

+

         while (battery_is_low() == 0) {

                 _cleanup_close_ int tfd = -1;

                 struct itimerspec ts = {};

@@ -287,14 +290,25 @@ static int custom_timer_suspend(const SleepConfig *sleep_config) {

                 if (r < 0)

                         return log_error_errno(r, "Error fetching battery capacity percentage: %m");

-                r = get_total_suspend_interval(last_capacity, &suspend_interval);

-                if (r < 0) {

-                        log_debug_errno(r, "Failed to estimate suspend interval using previous discharge rate, ignoring: %m");

-                        /* In case of no battery or any errors, system suspend interval will be set to HibernateDelaySec=. */

-                        suspend_interval = sleep_config->hibernate_delay_usec;

+                if (hashmap_isempty(last_capacity))

+                        /* In case of no battery, system suspend interval will be set to HibernateDelaySec= or 2 hours. */

+                        suspend_interval = timestamp_is_set(hibernate_timestamp) ? sleep_config->hibernate_delay_usec : DEFAULT_SUSPEND_ESTIMATION_USEC;

+                else {

+                        r = get_total_suspend_interval(last_capacity, &suspend_interval);

+                        if (r < 0) {

+                                log_debug_errno(r, "Failed to estimate suspend interval using previous discharge rate, ignoring: %m");

+                                /* In case of any errors, especially when we do not know the battery

+                                 * discharging rate, system suspend interval will be set to

+                                 * SuspendEstimationSec=. */

+                                suspend_interval = sleep_config->suspend_estimation_usec;

+                        }

                 }

+                /* Do not suspend more than HibernateDelaySec= */

                 usec_t before_timestamp = now(CLOCK_BOOTTIME);

+                suspend_interval = MIN(suspend_interval, usec_sub_unsigned(hibernate_timestamp, before_timestamp));

+                if (suspend_interval <= 0)

+                        break; /* system should hibernate */

                 log_debug("Set timerfd wake alarm for %s", FORMAT_TIMESPAN(suspend_interval, USEC_PER_SEC));

                 /* Wake alarm for system with or without battery to hibernate or estimate discharge rate whichever is applicable */

@@ -377,7 +391,7 @@ static int freeze_thaw_user_slice(const char **method) {

 static int execute_s2h(const SleepConfig *sleep_config) {

         _unused_ _cleanup_(freeze_thaw_user_slice) const char *auto_method_thaw = NULL;

-        int r, k;

+        int r;

         assert(sleep_config);

@@ -387,15 +401,21 @@ static int execute_s2h(const SleepConfig *sleep_config) {

         else

                 auto_method_thaw = "ThawUnit"; /* from now on we want automatic thawing */;

-        r = check_wakeup_type();

-        if (r < 0)

-                log_debug_errno(r, "Failed to check hardware wakeup type, ignoring: %m");

-

-        k = battery_trip_point_alarm_exists();

-        if (k < 0)

-                log_debug_errno(k, "Failed to check whether acpi_btp support is enabled or not, ignoring: %m");

+        /* Only check if we have automated battery alarms if HibernateDelaySec= is not set, as in that case

+         * we'll busy poll for the configured interval instead */

+        if (!timestamp_is_set(sleep_config->hibernate_delay_usec)) {

+                r = check_wakeup_type();

+                if (r < 0)

+                        log_debug_errno(r, "Failed to check hardware wakeup type, ignoring: %m");

+                else {

+                        r = battery_trip_point_alarm_exists();

+                        if (r < 0)

+                                log_debug_errno(r, "Failed to check whether acpi_btp support is enabled or not, ignoring: %m");

+                }

+        } else

+                r = 0;  /* Force fallback path */

-        if (r >= 0 && k > 0) {

+        if (r > 0) { /* If we have both wakeup alarms and battery trip point support, use them */

                 log_debug("Attempting to suspend...");

                 r = execute(sleep_config, SLEEP_SUSPEND, NULL);

                 if (r < 0)

diff --git a/src/sleep/sleep.conf b/src/sleep/sleep.conf

index a3d31140d8..4c8e8b9680 100644

--- a/src/sleep/sleep.conf

+++ b/src/sleep/sleep.conf

@@ -23,4 +23,5 @@

 #HibernateState=disk

 #HybridSleepMode=suspend platform shutdown

 #HybridSleepState=disk

-#HibernateDelaySec=120min

+#HibernateDelaySec=

+#SuspendEstimationSec=60min