NAME
apm
—
advanced power management device
interface
SYNOPSIS
apm0 at adb?
DESCRIPTION
The apm
driver provides an interface which
simulates the Advanced Power Management (APM) BIOS functions. The BIOS
functions are translated into the appropriate PowerManager requests.
Currently only battery level, AC connection, and charging status is
available from the apm
device. Suspend/resume and
other power events are NOT YET SUPPORTED.
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
- NOT YET SUPPORTED
on macppc (
no parameters
) Request “standby” mode. APM_IOC_SUSPEND
- NOT YET
SUPPORTED on macppc (
no parameters
) Request “suspend” mode. APM_IOC_GETPOWER
- (
struct apm_power_info
) Request the current power state. The argument 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
- Cannot 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 battery life available. 100% indicates a full charge.
If the battery is charging, i.e. when battery_state is equal to
APM_BATT_CHARGING
, the battery_life value contains the estimated number of minutes until the battery will be fully charged. Otherwise, the minutes_left value contains the estimated number of minutes of battery life remaining. APM_IOC_NEXTEVENT
- NOT YET
SUPPORTED on macppc (
struct apm_event_info
) The APM driver stores up toAPM_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 orEAGAIN
if the event list is empty. The format of the returned event is:struct apm_event_info { u_int type; u_int index; u_int spare[8]; };
APM_IOC_DEV_CTL
- NOT YET
SUPPORTED on macppc (
struct apm_ctl
) Allows an application to directly set the APM 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_IOC_PRN_CTL
- NOT YET
SUPPORTED on macppc (
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 estimated 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
. Settingmachdep.apmwarn
to zero disables all warnings regardless of theAPM_IOC_PRN_CTL
setting.
NOT YET SUPPORTED on macppc: 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
- Power management data device. May only be opened read-only. May be opened by multiple concurrent users.
- /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
EBUSY
.
SEE ALSO
adb(4), 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
Sleep modes and power events are not supported.