175 lines
6.0 KiB
Groff
175 lines
6.0 KiB
Groff
.\" Copyright (c) 1995,1996 John T. Kohl
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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.\" ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $NetBSD: apm.4,v 1.6 1999/09/09 03:52:22 itohy Exp $
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.\"
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.Dd May 18, 1996
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.Dt APM 4 i386
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.Os
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.Sh NAME
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.Nm apm
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.Nd
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Advanced Power Management pseudo-device driver
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.Sh SYNOPSIS
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.Cd "apm0 at mainbus0"
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.Fd #include <machine/apmvar.h>
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.Pa /dev/apm
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.Sh DESCRIPTION
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The
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.Nm apm
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driver provides support for the Advanced Power Managment features of
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some i386 system BIOSes. The driver supports the Advanced Power
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Management (APM) BIOS Interface Specification (revision 1.1), published
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jointly by the Intel Corporation and the Microsoft Corporation.
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.Pp
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The boot loader connects to the APM bios while the system is still
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operating in i386 real mode, and places the APM bios into 32-bit
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protected mode operation. The
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.Nx
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kernel start-up routines establish the 32-bit protected mode connection
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to the APM BIOS.
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.Pp
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The APM driver's behavior may be adjusted by specifying any of the
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following kernel configuration options:
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.Bl -tag -width indent -compact
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.It Dv APM_NO_IDLE
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Do not call the BIOS CPU idle function from the system idle loop. (Some
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systems will hang on certain device accesses, such as sound cards or
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floppy diskette drives, without this option)
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.It Dv APM_V10_ONLY
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Use only the APM revision 1.0 specification calls. (Some systems do not
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implement APM v1.1 very well, and generate weird events instead of the
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expected events when the system suspend key is pressed.)
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.It Dv APM_NO_POWEROFF
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Do not attempt to turn off power when halting the system.
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.It Dv APM_FORCE_64KSEG
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Force the length of the APM BIOS code and data segments to 64KB.
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.It Dv APMDEBUG
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Enable kernel printout of events received from the APM BIOS.
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.It Dv APMCALLDEBUG
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Enable kernel printout of every call to the APM BIOS (this is very noisy).
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.It Dv APM_NO_POWER_PRINT
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Do not print power state on console at
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.Dv APM_POWER_CHANGE
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events. (Some systems generate the events too frequently,
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and printing the status may disturb single-user operations.)
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.El
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.Pp
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If no processes are holding open file descriptors to the APM device, the
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driver will process the APM BIOS events itself. If a process has the
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device open for write, the driver defers all suspend and standby
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processing to the user process as long as there is sufficient queue
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space to store the event for the process. If the device is only open
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for read, the driver will report events but handle them itself.
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.Pp
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The APM device may be opened by multiple readers but only one
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writer. Multiple readers may fetch the status with
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.Xr ioctl 2
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without worrying about interference, but they must cooperate to share
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events as only a single event queue is provided. The device may only be
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.Xr select 2 ed
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or manipulated with
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.Xr ioctl 2 ;
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.Xr read 2
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and
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.Xr write 2
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are not supported.
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The
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.Xr ioctl 2
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calls supported are:
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.Bl -tag -width indent -compact
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.It Dv APM_IOC_SUSPEND
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Initiate an APM suspend mode. This is a deep sleep mode which powers down
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most devices. The device must be open for writing for this command to succeed.
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.It Dv APM_IOC_STANDBY
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Initiate an APM standby mode. This is a light sleep mode from which the
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system can quickly restore normal operation. The device must be open
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for writing for this command to succeed.
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.It Dv APM_IOC_GETPOWER
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Fetch the current power status into an
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.Va apm_power_info
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structure.
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.Bd -literal
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struct apm_power_info {
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u_char battery_state;
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u_char ac_state;
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u_char battery_life;
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u_char spare1;
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u_int minutes_left; /* estimate */
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u_int spare2[6];
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};
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.Ed
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.Va battery_state
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is one of
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.Dv APM_BATT_HIGH ,
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.Dv APM_BATT_LOW ,
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.Dv APM_BATT_CRITICAL ,
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.Dv APM_BATT_CHARGING ,
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or
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.Dv APM_BATT_UNKNOWN .
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.Va ac_state
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is one of
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.Dv APM_AC_OFF ,
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.Dv APM_AC_ON ,
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.Dv APM_AC_BACKUP ,
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or
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.Dv APM_AC_UNKNOWN .
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.Va battery_life
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is the percentage estimated remaining normal battery life (or 0 if the
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BIOS cannot provide an estimate).
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.Va minutes_left
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is an estimated remaining lifetime (or 0 if the BIOS cannot provide an
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estimate).
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.It Dv APM_IOC_NEXTEVENT
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Fetch the next event from the APM BIOS into an
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.Va apm_event_info
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structure. If no more events are ready, this will return
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.Dv EAGAIN .
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.Bd -literal
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struct apm_event_info {
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u_int type;
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u_int index;
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u_int spare[8];
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};
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.Ed
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.Va type
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is one of the APM event types (APM_STANDBY_REQ through
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APM_SYS_STANDBY_RESUME).
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.Va index
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is the ordinal event sequence number.
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.El
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.Sh SEE ALSO
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.Xr apmd 8
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.Sh REFERENCES
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Advanced Power Management (APM) BIOS Interface Specification (Revision
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1.1), Intel Corporation and Microsoft Corporation. Intel order number
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241704-001; Microsoft part number 781-110-X01.
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.Sh HISTORY
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The
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.Nm apm
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pseudo-device driver appeared in
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.Nx 1.3 .
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