sys-utils/rtcwake.8.in

   1 .\" Copyright (c) 2007, SUSE LINUX Products GmbH
   2 .\"                     Bernhard Walle <bwalle@suse.de>
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   5 .\" modify it under the terms of the GNU General Public License
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  19 .TH RTCWAKE 8 "July 2007" "util-linux" "System Administration"
  20 .SH NAME
  21 rtcwake - enter a system sleep state until specified wakeup time
  22 .SH SYNOPSIS
  23 .B rtcwake
  24 .RB [ options ]
  25 .RB [ \-d
  26 .IR device ]
  27 .RB [ \-m
  28 .IR standby_mode ]
  29 .RB { "\-t \fItime_t\fP" | "\-s \fIseconds\fP" }
  30 .SH DESCRIPTION
  31 This program is used to enter a system sleep state until specified wakeup time.
  32 .PP
  33 This uses cross-platform Linux interfaces to enter a system sleep state, and
  34 leave it no later than a specified time.  It uses any RTC framework driver that
  35 supports standard driver model wakeup flags.
  36 .PP
  37 This is normally used like the old \fBapmsleep\fP utility, to wake from a suspend
  38 state like ACPI S1 (standby) or S3 (suspend-to-RAM).  Most platforms can
  39 implement those without analogues of BIOS, APM, or ACPI.
  40 .P
  41 On some systems, this can also be used like \fBnvram-wakeup\fP, waking from states
  42 like ACPI S4 (suspend to disk).  Not all systems have persistent media that are
  43 appropriate for such suspend modes.
  44 .SS Options
  45 .TP
  46 \fB-v\fP | \fB--verbose\fP
  47 Be verbose.
  48 .TP
  49 \fB-h\fP | \fB--help\fP
  50 Display help text and exit.
  51 .TP
  52 \fB-V\fP | \fB--version\fP
  53 Display version information and exit.
  54 .TP
  55 \fB-n\fP | \fB--dry-run\fP
  56 This option does everything apart from actually setting up the alarm,
  57 suspending the system, or waiting for the alarm.
  58 .TP
  59 \fB-A\fP | \fB--adjfile\fP \fIfile\fP
  60 Specifies an alternative path to the adjust file.
  61 .TP
  62 \fB-a\fP | \fB--auto\fP
  63 Reads the clock mode (whether the hardware clock is set to UTC or local time)
  64 from \fIadjtime\fP file. That's the location where the
  65 .BR hwclock (8)
  66 stores that information. This is the default.
  67 .TP
  68 \fB-l\fP | \fB--local\fP
  69 Assumes that the hardware clock is set to local time, regardless of the
  70 contents of \fIadjtime\fP file.
  71 .TP
  72 \fB-u\fP | \fB--utc\fP
  73 Assumes that the hardware clock is set to UTC (Universal Time Coordinated),
  74 regardless of the contents of \fIadjtime\fP file.
  75 .TP
  76 \fB-d\fP \fIdevice\fP | \fB--device\fP \fIdevice\fP
  77 Uses \fIdevice\fP instead of \fIrtc0\fP as realtime clock. This option
  78 is only relevant if your system has more than one RTC. You may specify
  79 \fIrtc1\fP, \fIrtc2\fP, ... here.
  80 .TP
  81 \fB-s\fP \fIseconds\fP | \fB--seconds\fP \fIseconds\fP
  82 Sets the wakeup time to \fIseconds\fP in future from now.
  83 .TP
  84 \fB-t\fP \fItime_t\fP | \fB--time\fP \fItime_t\fP
  85 Sets the wakeup time to the absolute time \fItime_t\fP. \fItime_t\fP
  86 is the time in seconds since 1970-01-01, 00:00 UTC. Use the
  87 .BR date (1)
  88 tool to convert between human-readable time and \fItime_t\fP.
  89 .TP
  90 \fB-m\fP \fImode\fP | \fB--mode\fP \fImode\fP
  91 Use standby state \fImode\fP. Valid values are:
  92 .RS
  93 .TP
  94 .B standby
  95 ACPI state S1. This state offers minimal, though real, power savings, while
  96 providing a very low-latency transition back to a working system. This is the
  97 default mode.
  98 .TP
  99 .B mem
 100 ACPI state S3 (Suspend-to-RAM). This state offers significant power savings as
 101 everything in the system is put into a low-power state, except for memory,
 102 which is placed in self-refresh mode to retain its contents.
 103 .TP
 104 .B freeze
 105 The processes are frozen, all the devices are suspended and all the processors
 106 idles. This state is a general state that does not need any platform specific
 107 support, but it saves less power than susepnd to RAM, because the system is
 108 still in a running state. (since Linux 3.9)
 109 .TP
 110 .B disk
 111 ACPI state S4 (Suspend-to-disk). This state offers the greatest power savings,
 112 and can be used even in the absence of low-level platform support for power
 113 management. This state operates similarly to Suspend-to-RAM, but includes a
 114 final step of writing memory contents to disk.
 115 .TP
 116 .B off
 117 ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'.
 118 Not officially supported by ACPI, but usually working.
 119 .TP
 120 .B no
 121 Don't suspend. The rtcwake command sets RTC wakeup time only.
 122 .TP
 123 .B on
 124 Don't suspend, but read RTC device until alarm time appears. This mode is
 125 useful for debugging.
 126 .TP
 127 .B disable
 128 Disable previously set alarm.
 129 .TP
 130 .B show
 131 Print alarm information in format: "alarm: off|on  <time>".
 132 The time is in ctime() output format, e.g. "alarm: on  Tue Nov 16 04:48:45 2010".
 133 .RE
 134 .PP
 135 .SH FILES
 136 .I @ADJTIME_PATH@
 137 .SH NOTES
 138 Some PC systems can't currently exit sleep states such as \fImem\fP
 139 using only the kernel code accessed by this driver.
 140 They need help from userspace code to make the framebuffer work again.
 141 .SH HISTORY
 142 The program was posted several times on LKML and other lists
 143 before appearing in kernel commit message for Linux 2.6 in the GIT
 144 commit 87ac84f42a7a580d0dd72ae31d6a5eb4bfe04c6d.
 145 .SH AVAILABILITY
 146 The rtcwake command is part of the util-linux package and is available from
 147 ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
 148 .SH AUTHOR
 149 The program was written by David Brownell <dbrownell@users.sourceforge.net>
 150 and improved by Bernhard Walle <bwalle@suse.de>.
 151 .SH COPYRIGHT
 152 This is free software.  You may redistribute copies of it  under  the  terms
 153 of  the  GNU General  Public  License <http://www.gnu.org/licenses/gpl.html>.
 154 There is NO WARRANTY, to the extent permitted by law.
 155 .SH "SEE ALSO"
 156 .BR hwclock (8),
 157 .BR date (1)