MirOS Manual: apm(4)

APM(4)                  BSD Programmer's Manual (i386)                  APM(4)

NAME

     apm - advanced power management device interface

SYNOPSIS

     apm0 at bios0 flags 0x0000

DESCRIPTION

     The apm driver provides an interface to the Advanced Power Management
     (APM) BIOS functions. The driver supports versions 1.0, 1.1, and 1.2 in-
     terface specifications.

     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.

     The value of 0x10000 specifies whether to leave interrupts enabled when
     calling APM BIOS routines. This is needed for some IBM laptops, the symp-
     toms are hangs and freezes on suspend, stand by, and hibernation activi-
     ties.

     The value of 0x20000 specifies to swap the bytes of the battery life es-
     timation (the DX register) as given from the APM BIOS. This is needed for
     some SONY VAIO laptops, such as some 505 models.

     Configuration options:

           APMDEBUG    Enable various driver status messages.
           DIAGNOSTIC  Enable debugging messages.
           DEBUG       Enable other debugging messages.

     The apm driver implements the following ioctl(2) calls. They are defined
     in <machine/apmvar.h>.

     APM_IOC_REJECT
             Not implemented. DO NOT USE.

     APM_IOC_STANDBY
             (no parameters) Request "standby" mode.

     APM_IOC_SUSPEND
             (no parameters) Request "suspend" mode.

     APM_IOC_GETPOWER
             (struct apm_power_info) Request the current power state. The ar-
             gument structure is as follows:

                   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];
                   };

             The following values are defined for battery_state:

             APM_BATT_HIGH
                     Battery has a high state of charge.

             APM_BATT_LOW
                     Battery has a low state of charge.

             APM_BATT_CRITICAL
                     Battery has a critical state of charge.

             APM_BATT_CHARGING
                     Battery is not high, low, or critical and is currently
                     charging.

             APM_BATT_UNKNOWN
                     Can not read the current battery state.

             APM_BATTERY_ABSENT
                     No battery installed.

             The following values are defined for ac_state:

             APM_AC_OFF
                     External power not detected.

             APM_AC_ON
                     External power detected.

             APM_AC_BACKUP
                     Backup power in use.

             APM_AC_UNKNOWN
                     External power state unknown.

             The battery_life value contains the estimated percentage of bat-
             tery life available. 100% indicates a full charge.

             The minutes_left value contains the estimated number of minutes
             of battery life remaining.

     APM_IOC_NEXTEVENT
             (struct apm_event_info) The APM driver stores up to 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. APM_IOC_NEXTEVENT ioctl returns the next
             event on the list or EAGAIN if the event list is empty. The for-
             mat of the returned event is:

                   struct apm_event_info {
                           u_int type;
                           u_int index;
                           u_int spare[8];
                   };
             where index is a sequential count of events that can be used to
             check if any events were lost and type is one of:
                   APM_STANDBY_REQ
                   APM_SUSPEND_REQ
                   APM_NORMAL_RESUME
                   APM_CRIT_RESUME
                   APM_BATTERY_LOW
                   APM_POWER_CHANGE
                   APM_UPDATE_TIME
                   APM_CRIT_SUSPEND_REQ
                   APM_USER_STANDBY_REQ
                   APM_USER_SUSPEND_REQ
                   APM_SYS_STANDBY_RESUME

     APM_IOC_DEV_CTL
             (struct apm_ctl) Allows an application to directly set the
             operating mode. The argument structure is as follows:

                   struct apm_ctl {
                           u_int dev;
                           u_int mode;
                   };

             dev indicates the device, typically APM_DEV_ALLDEVS.

             mode indicates the desired operating mode. Possible values are
                   APM_SYS_READY
                   APM_SYS_STANDBY
                   APM_SYS_SUSPEND
                   APM_SYS_OFF
                   APM_LASTREQ_INPROG
                   APM_LASTREQ_REJECTED

     APM_IOC_PRN_CTL
             (int) This ioctl(2) controls message output by the APM driver
             when a power change event is detected. The integer parameter is
             one of:

             APM_PRINT_ON
                     All power change events result in a message. This is the
                     normal operating mode for the driver.

             APM_PRINT_OFF
                     Power change event messages are suppressed.

             APM_PRINT_PCT
                     Power change event messages are suppressed unless the es-
                     timated battery life percentage changes.

             However, in no case will power status messages be displayed until
             the battery life goes below the percentage in the sysctl(8) state
             variable machdep.apmwarn. Setting machdep.apmwarn to zero dis-
             ables all warnings regardless of the APM_IOC_PRN_CTL setting.

     As noted above, the operation of the APM driver can be modified using the
     machdep.apmwarn sysctl(8) variable. Another driver modifier is the
     machdep.apmhalt variable. When machdep.apmhalt is set to 1 the APM power
     down code is modified in a way necessary for correct operation on some
     systems, mainly IBM laptops. If your system does not power down when
     given the command halt -p try setting machdep.apmhalt to 1 using
     sysctl(8). The variable can be set at boot time in sysctl.conf(5).

FILES

     /dev/apm     APM data device. May only be opened read-only. May be opened
                  by multiple concurrent users.
     /dev/apmctl  APM 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 EBUSY.

SEE ALSO

     intro(4), sysctl.conf(5), apm(8), apmd(8), halt(8), sysctl(8)

HISTORY

     The apm driver source code contains these copyrights:

     Copyright (c) 1995 John T. Kohl. All rights reserved.
     Copyright (C) 1994 by HOSOKAWA Tatsumi <hosokawa@mt.cs.keio.ac.jp>

     ...and has been hacked on by many others since.

BUGS

     Not all the BIOSes support power down the way we are attempting to exe-
     cute it.

     Not all BIOS vendors even read the specification.

MirOS BSD #10-current           July 17, 1998                                2

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