.\" $OpenBSD: apm.4,v 1.30 2010/09/19 12:32:10 jmc Exp $ .\" .\" Copyright (c) 1998 Marco S. Hyman .\" .\" Permission to copy all or part of this material for any purpose is .\" granted provided that the above copyright notice and this paragraph .\" are duplicated in all copies. THIS SOFTWARE IS PROVIDED ``AS IS'' .\" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT .\" LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS .\" FOR A PARTICULAR PURPOSE. .\" .Dd $Mdocdate: September 19 2010 $ .Dt APM 4 i386 .Os .Sh NAME .Nm apm .Nd advanced power management device interface .Sh SYNOPSIS .Cd "apm0 at bios0 flags 0x0000" .Sh DESCRIPTION The .Nm driver provides an interface to the Advanced Power Management .Pq APM BIOS functions. The driver supports versions 1.0, 1.1, and 1.2 interface specifications. .Pp This driver also provides an interface to .Xr acpi 4 on some machines. .Pp The low two bytes of the flags specify the version of the specification driver should conform to in binary decimal notation. The value of 0x0101 would specify version 1.1 of the interface specification to be used. .Pp The value of 0x10000 specifies whether to leave interrupts enabled when calling APM BIOS routines. This is needed for some .Tn IBM laptops, the symptoms are hangs and freezes on suspend, stand by, and hibernation activities. .Pp The value of 0x20000 specifies to swap the bytes of the battery life estimation (the DX register) as given from the APM BIOS. This is needed for some .Tn SONY VAIO laptops, such as some 505 models. .Pp Configuration options: .Pp .Bl -tag -width DIAGNOSTIC -compact -offset indent .It Dv APMDEBUG Enable various driver status messages. .It Dv DIAGNOSTIC Enable debugging messages. .It Dv DEBUG Enable other debugging messages. .El .Pp The .Nm driver implements the following .Xr ioctl 2 calls. They are defined in .Aq Pa machine/apmvar.h . .Bl -tag -width Ds .It Dv APM_IOC_REJECT .Em Not implemented . DO NOT USE . .It Dv APM_IOC_STANDBY .Pq Li "no parameters" Request .Dq standby mode. .It Dv APM_IOC_SUSPEND .Pq Li "no parameters" Request .Dq suspend mode. .It Dv APM_IOC_GETPOWER .Pq Li "struct apm_power_info" Request the current power state. The argument structure is as follows: .Bd -literal -offset indent struct apm_power_info { u_char battery_state; u_char ac_state; u_char battery_life; u_char spare1; u_int minutes_left; u_int spare2[6]; }; .Ed .Pp The following values are defined for .Va battery_state : .Bl -tag -width Ds .It Dv APM_BATT_HIGH Battery has a high state of charge. .It Dv APM_BATT_LOW Battery has a low state of charge. .It Dv APM_BATT_CRITICAL Battery has a critical state of charge. .It Dv APM_BATT_CHARGING Battery is not high, low, or critical and is currently charging. .It Dv APM_BATT_UNKNOWN Can not read the current battery state. .It Dv APM_BATTERY_ABSENT No battery installed. .El .Pp The following values are defined for .Va ac_state : .Bl -tag -width Ds .It Dv APM_AC_OFF External power not detected. .It Dv APM_AC_ON External power detected. .It Dv APM_AC_BACKUP Backup power in use. .It Dv APM_AC_UNKNOWN External power state unknown. .El .Pp The .Va battery_life value contains the estimated percentage of battery life available. 100% indicates a full charge. .Pp The .Va minutes_left value contains the estimated number of minutes of battery life remaining. .It Dv APM_IOC_NEXTEVENT .Pq Li "struct apm_event_info" The APM driver stores up to .Dv APM_NEVENTS events. This was defined as 16 at the time this documentation was written. If the event list is full when a new event is detected the new event is lost. .Dv APM_IOC_NEXTEVENT ioctl returns the next event on the list or .Er EAGAIN if the event list is empty. The format of the returned event is: .Bd -literal -offset indent struct apm_event_info { u_int type; u_int index; u_int spare[8]; }; .Ed where .Va index is a sequential count of events that can be used to check if any events were lost and .Va type is one of: .Bl -tag -width Ds -offset indent -compact .It Dv APM_STANDBY_REQ .It Dv APM_SUSPEND_REQ .It Dv APM_NORMAL_RESUME .It Dv APM_CRIT_RESUME .It Dv APM_BATTERY_LOW .It Dv APM_POWER_CHANGE .It Dv APM_UPDATE_TIME .It Dv APM_CRIT_SUSPEND_REQ .It Dv APM_USER_STANDBY_REQ .It Dv APM_USER_SUSPEND_REQ .It Dv APM_SYS_STANDBY_RESUME .El .It Dv APM_IOC_DEV_CTL .Pq Li "struct apm_ctl" Allows an application to directly set the APM operating mode. The argument structure is as follows: .Bd -literal -offset indent struct apm_ctl { u_int dev; u_int mode; }; .Ed .Pp .Va dev indicates the device, typically .Dv APM_DEV_ALLDEVS . .Pp .Va mode indicates the desired operating mode. Possible values are .Bl -tag -width Ds -compact -offset indent .It Dv APM_SYS_READY .It Dv APM_SYS_STANDBY .It Dv APM_SYS_SUSPEND .It Dv APM_SYS_OFF .It Dv APM_LASTREQ_INPROG .It Dv APM_LASTREQ_REJECTED .El .It Dv APM_IOC_PRN_CTL .Pq Li "int" This .Xr ioctl 2 controls message output by the APM driver when a power change event is detected. The integer parameter is one of: .Bl -tag -width Ds .It Dv APM_PRINT_ON All power change events result in a message. This is the normal operating mode for the driver. .It Dv APM_PRINT_OFF Power change event messages are suppressed. .It Dv APM_PRINT_PCT Power change event messages are suppressed unless the estimated battery life percentage changes. .El .Pp However, in no case will power status messages be displayed until the battery life goes below the percentage in the .Xr sysctl 8 state variable .Dv machdep.apmwarn . Setting .Dv machdep.apmwarn to zero disables all warnings regardless of the .Dv APM_IOC_PRN_CTL setting. .El .Pp As noted above, the operation of the APM driver can be modified using the .Dv machdep.apmwarn .Xr sysctl 8 variable. Another driver modifier is the .Dv machdep.apmhalt variable. When .Dv machdep.apmhalt is set to 1 the APM power down code is modified in a way necessary for correct operation on some systems, mainly .Tn IBM laptops. If your system does not power down when given the command .Li "halt -p" try setting .Dv machdep.apmhalt to 1 using .Xr sysctl 8 . The variable can be set at boot time in .Xr sysctl.conf 5 . .Sh FILES .Bl -tag -width "/dev/apmctlXXX" .It /dev/apm Power management data device. May only be opened read-only. May be opened by multiple concurrent users. .It /dev/apmctl Power management control device. May be opened read-write or write-only. May only be opened by one user at a time. An attempt to open the file when in use will fail, returning .Er EBUSY . .El .Sh SEE ALSO .Xr acpi 4 , .Xr intro 4 , .Xr sysctl.conf 5 , .Xr apm 8 , .Xr apmd 8 , .Xr halt 8 , .Xr sysctl 8 .Sh HISTORY The .Nm driver source code contains these copyrights: .Pp .Bl -item -compact .It .Li Copyright (c) 1995 John T. Kohl. All rights reserved. .It .Li Copyright (C) 1994 by HOSOKAWA Tatsumi .El .Pp \&...and has been hacked on by many others since. .Sh BUGS Not all the BIOSes support power down the way we are attempting to execute it. .Pp Not all BIOS vendors even read the specification.