159 lines
5.8 KiB
Groff
159 lines
5.8 KiB
Groff
.\" Copyright (c) 2007, SUSE LINUX Products GmbH
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.\" Bernhard Walle <bwalle@suse.de>
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.\"
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.\" This program is free software; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License
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.\" as published by the Free Software Foundation; either version 2
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.\" of the License, or (at your option) any later version.
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.\"
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.\" This program is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public License
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.\" along with this program; if not, write to the Free Software
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.\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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.\" 02110-1301, USA.
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.\"
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.TH RTCWAKE 8 "July 2014" "util-linux" "System Administration"
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.SH NAME
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rtcwake \- enter a system sleep state until specified wakeup time
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.SH SYNOPSIS
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.B rtcwake
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[options]
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.RB [ \-d
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.IR device ]
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.RB [ \-m
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.IR standby_mode ]
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.RB { "\-s \fIseconds\fP" | "\-t \fItime_t\fP" }
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.SH DESCRIPTION
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This program is used to enter a system sleep state and to automatically
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wake from it at a specified time.
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.PP
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This uses cross-platform Linux interfaces to enter a system sleep state, and
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leave it no later than a specified time. It uses any RTC framework driver that
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supports standard driver model wakeup flags.
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.PP
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This is normally used like the old \fBapmsleep\fP utility, to wake from a suspend
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state like ACPI S1 (standby) or S3 (suspend-to-RAM). Most platforms can
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implement those without analogues of BIOS, APM, or ACPI.
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.PP
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On some systems, this can also be used like \fBnvram-wakeup\fP, waking from states
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like ACPI S4 (suspend to disk). Not all systems have persistent media that are
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appropriate for such suspend modes.
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.SH OPTIONS
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.TP
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.BR \-A , " \-\-adjfile " \fIfile
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Specify an alternative path to the adjust file.
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.TP
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.BR \-a , " \-\-auto"
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Read the clock mode (whether the hardware clock is set to UTC or local time)
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from the \fIadjtime\fP file, where
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.BR hwclock (8)
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stores that information. This is the default.
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.TP
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.BR \-d , " \-\-device " \fIdevice
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Use the specified \fIdevice\fP instead of \fBrtc0\fP as realtime clock.
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This option is only relevant if your system has more than one RTC.
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You may specify \fBrtc1\fP, \fBrtc2\fP, ... here.
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.TP
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.BR \-l , " \-\-local"
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Assume that the hardware clock is set to local time, regardless of the
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contents of the \fIadjtime\fP file.
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.TP
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.BR \-m , " \-\-mode " \fImode
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Go into the given standby state. Valid values for \fImode\fP are:
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.RS
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.TP
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.B standby
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ACPI state S1. This state offers minimal, though real, power savings, while
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providing a very low-latency transition back to a working system. This is the
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default mode.
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.TP
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.B freeze
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The processes are frozen, all the devices are suspended and all the processors
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idled. This state is a general state that does not need any platform-specific
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support, but it saves less power than Suspend-to-RAM, because the system is
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still in a running state. (Available since Linux 3.9.)
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.TP
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.B mem
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ACPI state S3 (Suspend-to-RAM). This state offers significant power savings as
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everything in the system is put into a low-power state, except for memory,
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which is placed in self-refresh mode to retain its contents.
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.TP
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.B disk
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ACPI state S4 (Suspend-to-disk). This state offers the greatest power savings,
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and can be used even in the absence of low-level platform support for power
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management. This state operates similarly to Suspend-to-RAM, but includes a
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final step of writing memory contents to disk.
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.TP
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.B off
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ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'.
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Not officially supported by ACPI, but it usually works.
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.TP
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.B no
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Don't suspend, only set the RTC wakeup time.
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.TP
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.B on
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Don't suspend, but read the RTC device until an alarm time appears.
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This mode is useful for debugging.
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.TP
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.B disable
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Disable a previously set alarm.
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.TP
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.B show
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Print alarm information in format: "alarm: off|on <time>".
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The time is in ctime() output format, e.g. "alarm: on Tue Nov 16 04:48:45 2010".
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.RE
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.TP
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.BR \-n , " \-\-dry-run"
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This option does everything apart from actually setting up the alarm,
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suspending the system, or waiting for the alarm.
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.TP
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.BR \-s , " \-\-seconds " \fIseconds
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Set the wakeup time to \fIseconds\fP in the future from now.
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.TP
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.BR \-t , " \-\-time " \fItime_t
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Set the wakeup time to the absolute time \fItime_t\fP. \fItime_t\fP
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is the time in seconds since 1970-01-01, 00:00 UTC. Use the
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.BR date (1)
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tool to convert between human-readable time and \fItime_t\fP.
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.TP
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.BR \-u , " \-\-utc"
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Assume that the hardware clock is set to UTC (Universal Time Coordinated),
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regardless of the contents of the \fIadjtime\fP file.
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.TP
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.BR \-v , " \-\-verbose"
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Be verbose.
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.TP
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.BR \-V , " \-\-version"
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Display version information and exit.
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.TP
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.BR \-h , " \-\-help"
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Display help text and exit.
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.SH NOTES
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Some PC systems can't currently exit sleep states such as \fBmem\fP
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using only the kernel code accessed by this driver.
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They need help from userspace code to make the framebuffer work again.
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.SH FILES
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.I @ADJTIME_PATH@
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.SH HISTORY
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The program was posted several times on LKML and other lists
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before appearing in kernel commit message for Linux 2.6 in the GIT
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commit 87ac84f42a7a580d0dd72ae31d6a5eb4bfe04c6d.
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.SH AUTHORS
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The program was written by David Brownell <dbrownell@users.sourceforge.net>
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and improved by Bernhard Walle <bwalle@suse.de>.
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.SH COPYRIGHT
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This is free software. You may redistribute copies of it under the terms
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of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
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There is NO WARRANTY, to the extent permitted by law.
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.SH "SEE ALSO"
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.BR hwclock (8),
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.BR date (1)
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.SH AVAILABILITY
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The rtcwake command is part of the util-linux package and is available from the
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.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
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Linux Kernel Archive
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.UE . |