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Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-apm

Browse source 
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-apm:
  [APM] SH: Convert to use shared APM emulation.
  [APM] MIPS: Convert to use shared APM emulation.
  [APM] ARM: Convert to use shared APM emulation.
  [APM] Add shared version of APM emulation
This commit is contained in:
Linus Torvalds 2007-02-09 09:44:28 -08:00
parent 2affc857ef 0a9b0db192
commit 2fd592e45b
19 changed files with 78 additions and 1368 deletions
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29
arch/arm/Kconfig
View file

@ -9,6 +9,7 @@ config ARM
bool
default y
select RTC_LIB
select SYS_SUPPORTS_APM_EMULATION
help
The ARM series is a line of low-power-consumption RISC chip designs
licensed by ARM Ltd and targeted at embedded applications and
@ -17,6 +18,9 @@ config ARM
Europe. There is an ARM Linux project with a web page at
<http://www.arm.linux.org.uk/>.
config SYS_SUPPORTS_APM_EMULATION
bool
config GENERIC_TIME
bool
default n
@ -856,31 +860,6 @@ menu "Power management options"
source "kernel/power/Kconfig"
config APM
tristate "Advanced Power Management Emulation"
---help---
APM is a BIOS specification for saving power using several different
techniques. This is mostly useful for battery powered laptops with
APM compliant BIOSes. If you say Y here, the system time will be
reset after a RESUME operation, the /proc/apm device will provide
battery status information, and user-space programs will receive
notification of APM "events" (e.g. battery status change).
In order to use APM, you will need supporting software. For location
and more information, read <file:Documentation/pm.txt> and the
Battery Powered Linux mini-HOWTO, available from
<http://www.tldp.org/docs.html#howto>.
This driver does not spin down disk drives (see the hdparm(8)
manpage ("man 8 hdparm") for that), and it doesn't turn off
VESA-compliant "green" monitors.
Generally, if you don't have a battery in your machine, there isn't
much point in using this driver and you should say N. If you get
random kernel OOPSes or reboots that don't seem to be related to
anything, try disabling/enabling this option (or disabling/enabling
APM in your BIOS).
endmenu
source "net/Kconfig"

2
arch/arm/common/sharpsl_pm.c
View file

@ -27,7 +27,7 @@
#include <asm/hardware.h>
#include <asm/mach-types.h>
#include <asm/irq.h>
#include <asm/apm.h>
#include <asm/apm-emulation.h>
#include <asm/arch/pm.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/sharpsl.h>

1
arch/arm/kernel/Makefile
View file

@ -10,7 +10,6 @@ obj-y := compat.o entry-armv.o entry-common.o irq.o \
process.o ptrace.o semaphore.o setup.o signal.o sys_arm.o \
time.o traps.o
obj-$(CONFIG_APM) += apm.o
obj-$(CONFIG_ISA_DMA_API) += dma.o
obj-$(CONFIG_ARCH_ACORN) += ecard.o
obj-$(CONFIG_FIQ) += fiq.o

2
arch/arm/mach-pxa/corgi_pm.c
View file

@ -16,7 +16,7 @@
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/apm.h>
#include <asm/apm-emulation.h>
#include <asm/irq.h>
#include <asm/mach-types.h>
#include <asm/hardware.h>

2
arch/arm/mach-pxa/sharpsl_pm.c
View file

@ -23,7 +23,7 @@
#include <asm/hardware.h>
#include <asm/mach-types.h>
#include <asm/apm.h>
#include <asm/apm-emulation.h>
#include <asm/arch/pm.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/sharpsl.h>

2
arch/arm/mach-pxa/spitz_pm.c
View file

@ -16,7 +16,7 @@
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/apm.h>
#include <asm/apm-emulation.h>
#include <asm/irq.h>
#include <asm/mach-types.h>
#include <asm/hardware.h>

34
arch/mips/Kconfig
View file

@ -934,6 +934,9 @@ config CPU_LITTLE_ENDIAN
endchoice
config SYS_SUPPORTS_APM_EMULATION
bool
config SYS_SUPPORTS_BIG_ENDIAN
bool
@ -1001,6 +1004,7 @@ config SOC_AU1X00
bool
select SYS_HAS_CPU_MIPS32_R1
select SYS_SUPPORTS_32BIT_KERNEL
select SYS_SUPPORTS_APM_EMULATION
config PNX8550
bool
@ -2071,35 +2075,11 @@ config BINFMT_ELF32
bool
default y if MIPS32_O32 || MIPS32_N32
config PM
bool "Power Management support (EXPERIMENTAL)"
depends on EXPERIMENTAL && SOC_AU1X00
endmenu
config APM
tristate "Advanced Power Management Emulation"
depends on PM
---help---
APM is a BIOS specification for saving power using several different
techniques. This is mostly useful for battery powered systems with
APM compliant BIOSes. If you say Y here, the system time will be
reset after a RESUME operation, the /proc/apm device will provide
battery status information, and user-space programs will receive
notification of APM "events" (e.g. battery status change).
menu "Power management options"
In order to use APM, you will need supporting software. For location
and more information, read <file:Documentation/pm.txt> and the
Battery Powered Linux mini-HOWTO, available from
<http://www.tldp.org/docs.html#howto>.
This driver does not spin down disk drives (see the hdparm(8)
manpage ("man 8 hdparm") for that), and it doesn't turn off
VESA-compliant "green" monitors.
Generally, if you don't have a battery in your machine, there isn't
much point in using this driver and you should say N. If you get
random kernel OOPSes or reboots that don't seem to be related to
anything, try disabling/enabling this option (or disabling/enabling
APM in your BIOS).
source "kernel/power/Kconfig"
endmenu

2
arch/mips/kernel/Makefile
View file

@ -14,8 +14,6 @@ binfmt_irix-objs := irixelf.o irixinv.o irixioctl.o irixsig.o \
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_MODULES) += mips_ksyms.o module.o
obj-$(CONFIG_APM) += apm.o
obj-$(CONFIG_CPU_R3000) += r2300_fpu.o r2300_switch.o
obj-$(CONFIG_CPU_TX39XX) += r2300_fpu.o r2300_switch.o
obj-$(CONFIG_CPU_TX49XX) += r4k_fpu.o r4k_switch.o

604
arch/mips/kernel/apm.c
View file

@ -1,604 +0,0 @@
/*
* bios-less APM driver for MIPS Linux
* Jamey Hicks <jamey@crl.dec.com>
* adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com)
*
* APM 1.2 Reference:
* Intel Corporation, Microsoft Corporation. Advanced Power Management
* (APM) BIOS Interface Specification, Revision 1.2, February 1996.
*
* [This document is available from Microsoft at:
* http://www.microsoft.com/hwdev/busbios/amp_12.htm]
*/
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/apm_bios.h>
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <asm/apm.h> /* apm_power_info */
#include <asm/system.h>
/*
* The apm_bios device is one of the misc char devices.
* This is its minor number.
*/
#define APM_MINOR_DEV 134
/*
* See Documentation/Config.help for the configuration options.
*
* Various options can be changed at boot time as follows:
* (We allow underscores for compatibility with the modules code)
* apm=on/off enable/disable APM
*/
/*
* Maximum number of events stored
*/
#define APM_MAX_EVENTS 16
struct apm_queue {
unsigned int event_head;
unsigned int event_tail;
apm_event_t events[APM_MAX_EVENTS];
};
/*
* The per-file APM data
*/
struct apm_user {
struct list_head list;
unsigned int suser: 1;
unsigned int writer: 1;
unsigned int reader: 1;
int suspend_result;
unsigned int suspend_state;
#define SUSPEND_NONE 0 /* no suspend pending */
#define SUSPEND_PENDING 1 /* suspend pending read */
#define SUSPEND_READ 2 /* suspend read, pending ack */
#define SUSPEND_ACKED 3 /* suspend acked */
#define SUSPEND_DONE 4 /* suspend completed */
struct apm_queue queue;
};
/*
* Local variables
*/
static int suspends_pending;
static int apm_disabled;
static int mips_apm_active;
static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
/*
* This is a list of everyone who has opened /dev/apm_bios
*/
static DECLARE_RWSEM(user_list_lock);
static LIST_HEAD(apm_user_list);
/*
* kapmd info. kapmd provides us a process context to handle
* "APM" events within - specifically necessary if we're going
* to be suspending the system.
*/
static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait);
static DECLARE_COMPLETION(kapmd_exit);
static DEFINE_SPINLOCK(kapmd_queue_lock);
static struct apm_queue kapmd_queue;
static const char driver_version[] = "1.13"; /* no spaces */
/*
* Compatibility cruft until the IPAQ people move over to the new
* interface.
*/
static void __apm_get_power_status(struct apm_power_info *info)
{
}
/*
* This allows machines to provide their own "apm get power status" function.
*/
void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status;
EXPORT_SYMBOL(apm_get_power_status);
/*
* APM event queue management.
*/
static inline int queue_empty(struct apm_queue *q)
{
return q->event_head == q->event_tail;
}
static inline apm_event_t queue_get_event(struct apm_queue *q)
{
q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
return q->events[q->event_tail];
}
static void queue_add_event(struct apm_queue *q, apm_event_t event)
{
q->event_head = (q->event_head + 1) % APM_MAX_EVENTS;
if (q->event_head == q->event_tail) {
static int notified;
if (notified++ == 0)
printk(KERN_ERR "apm: an event queue overflowed\n");
q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
}
q->events[q->event_head] = event;
}
static void queue_event_one_user(struct apm_user *as, apm_event_t event)
{
if (as->suser && as->writer) {
switch (event) {
case APM_SYS_SUSPEND:
case APM_USER_SUSPEND:
/*
* If this user already has a suspend pending,
* don't queue another one.
*/
if (as->suspend_state != SUSPEND_NONE)
return;
as->suspend_state = SUSPEND_PENDING;
suspends_pending++;
break;
}
}
queue_add_event(&as->queue, event);
}
static void queue_event(apm_event_t event, struct apm_user *sender)
{
struct apm_user *as;
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list) {
if (as != sender && as->reader)
queue_event_one_user(as, event);
}
up_read(&user_list_lock);
wake_up_interruptible(&apm_waitqueue);
}
static void apm_suspend(void)
{
struct apm_user *as;
int err = pm_suspend(PM_SUSPEND_MEM);
/*
* Anyone on the APM queues will think we're still suspended.
* Send a message so everyone knows we're now awake again.
*/
queue_event(APM_NORMAL_RESUME, NULL);
/*
* Finally, wake up anyone who is sleeping on the suspend.
*/
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list) {
as->suspend_result = err;
as->suspend_state = SUSPEND_DONE;
}
up_read(&user_list_lock);
wake_up(&apm_suspend_waitqueue);
}
static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
{
struct apm_user *as = fp->private_data;
apm_event_t event;
int i = count, ret = 0;
if (count < sizeof(apm_event_t))
return -EINVAL;
if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK)
return -EAGAIN;
wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue));
while ((i >= sizeof(event)) && !queue_empty(&as->queue)) {
event = queue_get_event(&as->queue);
ret = -EFAULT;
if (copy_to_user(buf, &event, sizeof(event)))
break;
if (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND)
as->suspend_state = SUSPEND_READ;
buf += sizeof(event);
i -= sizeof(event);
}
if (i < count)
ret = count - i;
return ret;
}
static unsigned int apm_poll(struct file *fp, poll_table * wait)
{
struct apm_user *as = fp->private_data;
poll_wait(fp, &apm_waitqueue, wait);
return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM;
}
/*
* apm_ioctl - handle APM ioctl
*
* APM_IOC_SUSPEND
* This IOCTL is overloaded, and performs two functions. It is used to:
* - initiate a suspend
* - acknowledge a suspend read from /dev/apm_bios.
* Only when everyone who has opened /dev/apm_bios with write permission
* has acknowledge does the actual suspend happen.
*/
static int
apm_ioctl(struct inode * inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
struct apm_user *as = filp->private_data;
unsigned long flags;
int err = -EINVAL;
if (!as->suser || !as->writer)
return -EPERM;
switch (cmd) {
case APM_IOC_SUSPEND:
as->suspend_result = -EINTR;
if (as->suspend_state == SUSPEND_READ) {
/*
* If we read a suspend command from /dev/apm_bios,
* then the corresponding APM_IOC_SUSPEND ioctl is
* interpreted as an acknowledge.
*/
as->suspend_state = SUSPEND_ACKED;
suspends_pending--;
} else {
/*
* Otherwise it is a request to suspend the system.
* Queue an event for all readers, and expect an
* acknowledge from all writers who haven't already
* acknowledged.
*/
queue_event(APM_USER_SUSPEND, as);
}
/*
* If there are no further acknowledges required, suspend
* the system.
*/
if (suspends_pending == 0)
apm_suspend();
/*
* Wait for the suspend/resume to complete. If there are
* pending acknowledges, we wait here for them.
*
* Note that we need to ensure that the PM subsystem does
* not kick us out of the wait when it suspends the threads.
*/
flags = current->flags;
current->flags |= PF_NOFREEZE;
/*
* Note: do not allow a thread which is acking the suspend
* to escape until the resume is complete.
*/
if (as->suspend_state == SUSPEND_ACKED)
wait_event(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
else
wait_event_interruptible(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
current->flags = flags;
err = as->suspend_result;
as->suspend_state = SUSPEND_NONE;
break;
}
return err;
}
static int apm_release(struct inode * inode, struct file * filp)
{
struct apm_user *as = filp->private_data;
filp->private_data = NULL;
down_write(&user_list_lock);
list_del(&as->list);
up_write(&user_list_lock);
/*
* We are now unhooked from the chain. As far as new
* events are concerned, we no longer exist. However, we
* need to balance suspends_pending, which means the
* possibility of sleeping.
*/
if (as->suspend_state != SUSPEND_NONE) {
suspends_pending -= 1;
if (suspends_pending == 0)
apm_suspend();
}
kfree(as);
return 0;
}
static int apm_open(struct inode * inode, struct file * filp)
{
struct apm_user *as;
as = kzalloc(sizeof(*as), GFP_KERNEL);
if (as) {
/*
* XXX - this is a tiny bit broken, when we consider BSD
* process accounting. If the device is opened by root, we
* instantly flag that we used superuser privs. Who knows,
* we might close the device immediately without doing a
* privileged operation -- cevans
*/
as->suser = capable(CAP_SYS_ADMIN);
as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
down_write(&user_list_lock);
list_add(&as->list, &apm_user_list);
up_write(&user_list_lock);
filp->private_data = as;
}
return as ? 0 : -ENOMEM;
}
static struct file_operations apm_bios_fops = {
.owner = THIS_MODULE,
.read = apm_read,
.poll = apm_poll,
.ioctl = apm_ioctl,
.open = apm_open,
.release = apm_release,
};
static struct miscdevice apm_device = {
.minor = APM_MINOR_DEV,
.name = "apm_bios",
.fops = &apm_bios_fops
};
#ifdef CONFIG_PROC_FS
/*
* Arguments, with symbols from linux/apm_bios.h.
*
* 0) Linux driver version (this will change if format changes)
* 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2.
* 2) APM flags from APM Installation Check (0x00):
* bit 0: APM_16_BIT_SUPPORT
* bit 1: APM_32_BIT_SUPPORT
* bit 2: APM_IDLE_SLOWS_CLOCK
* bit 3: APM_BIOS_DISABLED
* bit 4: APM_BIOS_DISENGAGED
* 3) AC line status
* 0x00: Off-line
* 0x01: On-line
* 0x02: On backup power (BIOS >= 1.1 only)
* 0xff: Unknown
* 4) Battery status
* 0x00: High
* 0x01: Low
* 0x02: Critical
* 0x03: Charging
* 0x04: Selected battery not present (BIOS >= 1.2 only)
* 0xff: Unknown
* 5) Battery flag
* bit 0: High
* bit 1: Low
* bit 2: Critical
* bit 3: Charging
* bit 7: No system battery
* 0xff: Unknown
* 6) Remaining battery life (percentage of charge):
* 0-100: valid
* -1: Unknown
* 7) Remaining battery life (time units):
* Number of remaining minutes or seconds
* -1: Unknown
* 8) min = minutes; sec = seconds
*/
static int apm_get_info(char *buf, char **start, off_t fpos, int length)
{
struct apm_power_info info;
char *units;
int ret;
info.ac_line_status = 0xff;
info.battery_status = 0xff;
info.battery_flag = 0xff;
info.battery_life = -1;
info.time = -1;
info.units = -1;
if (apm_get_power_status)
apm_get_power_status(&info);
switch (info.units) {
default: units = "?"; break;
case 0: units = "min"; break;
case 1: units = "sec"; break;
}
ret = sprintf(buf, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
driver_version, APM_32_BIT_SUPPORT,
info.ac_line_status, info.battery_status,
info.battery_flag, info.battery_life,
info.time, units);
return ret;
}
#endif
static int kapmd(void *arg)
{
daemonize("kapmd");
current->flags |= PF_NOFREEZE;
do {
apm_event_t event;
wait_event_interruptible(kapmd_wait,
!queue_empty(&kapmd_queue) || !mips_apm_active);
if (!mips_apm_active)
break;
spin_lock_irq(&kapmd_queue_lock);
event = 0;
if (!queue_empty(&kapmd_queue))
event = queue_get_event(&kapmd_queue);
spin_unlock_irq(&kapmd_queue_lock);
switch (event) {
case 0:
break;
case APM_LOW_BATTERY:
case APM_POWER_STATUS_CHANGE:
queue_event(event, NULL);
break;
case APM_USER_SUSPEND:
case APM_SYS_SUSPEND:
queue_event(event, NULL);
if (suspends_pending == 0)
apm_suspend();
break;
case APM_CRITICAL_SUSPEND:
apm_suspend();
break;
}
} while (1);
complete_and_exit(&kapmd_exit, 0);
}
static int __init apm_init(void)
{
int ret;
if (apm_disabled) {
printk(KERN_NOTICE "apm: disabled on user request.\n");
return -ENODEV;
}
mips_apm_active = 1;
ret = kernel_thread(kapmd, NULL, CLONE_KERNEL);
if (ret < 0) {
mips_apm_active = 0;
return ret;
}
#ifdef CONFIG_PROC_FS
create_proc_info_entry("apm", 0, NULL, apm_get_info);
#endif
ret = misc_register(&apm_device);
if (ret != 0) {
remove_proc_entry("apm", NULL);
mips_apm_active = 0;
wake_up(&kapmd_wait);
wait_for_completion(&kapmd_exit);
}
return ret;
}
static void __exit apm_exit(void)
{
misc_deregister(&apm_device);
remove_proc_entry("apm", NULL);
mips_apm_active = 0;
wake_up(&kapmd_wait);
wait_for_completion(&kapmd_exit);
}
module_init(apm_init);
module_exit(apm_exit);
MODULE_AUTHOR("Stephen Rothwell");
MODULE_DESCRIPTION("Advanced Power Management");
MODULE_LICENSE("GPL");
#ifndef MODULE
static int __init apm_setup(char *str)
{
while ((str != NULL) && (*str != '\0')) {
if (strncmp(str, "off", 3) == 0)
apm_disabled = 1;
if (strncmp(str, "on", 2) == 0)
apm_disabled = 0;
str = strchr(str, ',');
if (str != NULL)
str += strspn(str, ", \t");
}
return 1;
}
__setup("apm=", apm_setup);
#endif
/**
* apm_queue_event - queue an APM event for kapmd
* @event: APM event
*
* Queue an APM event for kapmd to process and ultimately take the
* appropriate action. Only a subset of events are handled:
* %APM_LOW_BATTERY
* %APM_POWER_STATUS_CHANGE
* %APM_USER_SUSPEND
* %APM_SYS_SUSPEND
* %APM_CRITICAL_SUSPEND
*/
void apm_queue_event(apm_event_t event)
{
unsigned long flags;
spin_lock_irqsave(&kapmd_queue_lock, flags);
queue_add_event(&kapmd_queue, event);
spin_unlock_irqrestore(&kapmd_queue_lock, flags);
wake_up_interruptible(&kapmd_wait);
}
EXPORT_SYMBOL(apm_queue_event);

7
arch/sh/Kconfig
View file

@ -48,6 +48,9 @@ config GENERIC_IOMAP
config GENERIC_TIME
def_bool n
config SYS_SUPPORTS_APM_EMULATION
bool
config ARCH_MAY_HAVE_PC_FDC
bool
@ -126,6 +129,7 @@ config SH_7751_SYSTEMH
config SH_HP6XX
bool "HP6XX"
select SYS_SUPPORTS_APM_EMULATION
help
Select HP6XX if configuring for a HP jornada HP6xx.
More information (hardware only) at
@ -694,9 +698,6 @@ depends on EXPERIMENTAL
source kernel/power/Kconfig
config APM
bool "Advanced Power Management Emulation"
depends on PM
endmenu
source "net/Kconfig"

68
arch/sh/boards/hp6xx/hp6xx_apm.c
View file

@ -7,12 +7,11 @@
* modify it under the terms of the GNU General Public License.
*/
#include <linux/module.h>
#include <linux/apm_bios.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <asm/apm.h>
#include <linux/apm-emulation.h>
#include <linux/io.h>
#include <asm/adc.h>
#include <asm/hp6xx.h>
@ -27,60 +26,41 @@
#define MODNAME "hp6x0_apm"
static int hp6x0_apm_get_info(char *buf, char **start, off_t fpos, int length)
static void hp6x0_apm_get_power_status(struct apm_power_info *info)
{
int battery, backup, charging, percentage;
u8 pgdr;
char *p;
int battery_status;
int battery_flag;
int ac_line_status;
int time_units = APM_BATTERY_LIFE_UNKNOWN;
int battery = adc_single(ADC_CHANNEL_BATTERY);
int backup = adc_single(ADC_CHANNEL_BACKUP);
int charging = adc_single(ADC_CHANNEL_CHARGE);
int percentage;
battery = adc_single(ADC_CHANNEL_BATTERY);
backup = adc_single(ADC_CHANNEL_BACKUP);
charging = adc_single(ADC_CHANNEL_CHARGE);
percentage = 100 * (battery - HP680_BATTERY_MIN) /
(HP680_BATTERY_MAX - HP680_BATTERY_MIN);
ac_line_status = (battery > HP680_BATTERY_AC_ON) ?
info->ac_line_status = (battery > HP680_BATTERY_AC_ON) ?
APM_AC_ONLINE : APM_AC_OFFLINE;
p = buf;
pgdr = ctrl_inb(SH7709_PGDR);
if (pgdr & PGDR_MAIN_BATTERY_OUT) {
battery_status = APM_BATTERY_STATUS_NOT_PRESENT;
battery_flag = 0x80;
percentage = -1;
} else if (charging < 8 ) {
battery_status = APM_BATTERY_STATUS_CHARGING;
battery_flag = 0x08;
ac_line_status = 0xff;
info->battery_status = APM_BATTERY_STATUS_NOT_PRESENT;
info->battery_flag = 0x80;
} else if (charging < 8) {
info->battery_status = APM_BATTERY_STATUS_CHARGING;
info->battery_flag = 0x08;
info->ac_line_status = 0xff;
} else if (percentage <= APM_CRITICAL) {
battery_status = APM_BATTERY_STATUS_CRITICAL;
battery_flag = 0x04;
info->battery_status = APM_BATTERY_STATUS_CRITICAL;
info->battery_flag = 0x04;
} else if (percentage <= APM_LOW) {
battery_status = APM_BATTERY_STATUS_LOW;
battery_flag = 0x02;
info->battery_status = APM_BATTERY_STATUS_LOW;
info->battery_flag = 0x02;
} else {
battery_status = APM_BATTERY_STATUS_HIGH;
battery_flag = 0x01;
info->battery_status = APM_BATTERY_STATUS_HIGH;
info->battery_flag = 0x01;
}
p += sprintf(p, "1.0 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
APM_32_BIT_SUPPORT,
ac_line_status,
battery_status,
battery_flag,
percentage,
time_units,
"min");
p += sprintf(p, "bat=%d backup=%d charge=%d\n",
battery, backup, charging);
return p - buf;
info->units = 0;
}
static irqreturn_t hp6x0_apm_interrupt(int irq, void *dev)
@ -96,14 +76,14 @@ static int __init hp6x0_apm_init(void)
int ret;
ret = request_irq(HP680_BTN_IRQ, hp6x0_apm_interrupt,
IRQF_DISABLED, MODNAME, 0);
IRQF_DISABLED, MODNAME, NULL);
if (unlikely(ret < 0)) {
printk(KERN_ERR MODNAME ": IRQ %d request failed\n",
HP680_BTN_IRQ);
return ret;
}
apm_get_info = hp6x0_apm_get_info;
apm_get_power_status = hp6x0_apm_get_power_status;
return ret;
}
@ -111,7 +91,7 @@ static int __init hp6x0_apm_init(void)
static void __exit hp6x0_apm_exit(void)
{
free_irq(HP680_BTN_IRQ, 0);
apm_get_info = 0;
apm_get_info = NULL;
}
module_init(hp6x0_apm_init);

1
arch/sh/kernel/Makefile
View file

@ -19,6 +19,5 @@ obj-$(CONFIG_SH_CPU_FREQ) += cpufreq.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_APM) += apm.o
obj-$(CONFIG_PM) += pm.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o

538
arch/sh/kernel/apm.c
View file

@ -1,538 +0,0 @@
/*
* bios-less APM driver for hp680
*
* Copyright 2005 (c) Andriy Skulysh <askulysh@gmail.com>
*
* based on ARM APM driver by
* Jamey Hicks <jamey@crl.dec.com>
*
* adapted from the APM BIOS driver for Linux by
* Stephen Rothwell (sfr@linuxcare.com)
*
* APM 1.2 Reference:
* Intel Corporation, Microsoft Corporation. Advanced Power Management
* (APM) BIOS Interface Specification, Revision 1.2, February 1996.
*
* [This document is available from Microsoft at:
* http://www.microsoft.com/hwdev/busbios/amp_12.htm]
*/
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/apm_bios.h>
#include <linux/pm.h>
#include <linux/pm_legacy.h>
#include <asm/apm.h>
#define MODNAME "apm"
/*
* The apm_bios device is one of the misc char devices.
* This is its minor number.
*/
#define APM_MINOR_DEV 134
/*
* Maximum number of events stored
*/
#define APM_MAX_EVENTS 16
struct apm_queue {
unsigned int event_head;
unsigned int event_tail;
apm_event_t events[APM_MAX_EVENTS];
};
/*
* The per-file APM data
*/
struct apm_user {
struct list_head list;
unsigned int suser: 1;
unsigned int writer: 1;
unsigned int reader: 1;
int suspend_result;
unsigned int suspend_state;
#define SUSPEND_NONE 0 /* no suspend pending */
#define SUSPEND_PENDING 1 /* suspend pending read */
#define SUSPEND_READ 2 /* suspend read, pending ack */
#define SUSPEND_ACKED 3 /* suspend acked */
#define SUSPEND_DONE 4 /* suspend completed */
struct apm_queue queue;
};
/*
* Local variables
*/
static int suspends_pending;
static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
/*
* This is a list of everyone who has opened /dev/apm_bios
*/
static DECLARE_RWSEM(user_list_lock);
static LIST_HEAD(apm_user_list);
/*
* kapmd info. kapmd provides us a process context to handle
* "APM" events within - specifically necessary if we're going
* to be suspending the system.
*/
static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait);
static DECLARE_COMPLETION(kapmd_exit);
static DEFINE_SPINLOCK(kapmd_queue_lock);
static struct apm_queue kapmd_queue;
int apm_suspended;
EXPORT_SYMBOL(apm_suspended);
/* Platform-specific apm_read_proc(). */
int (*apm_get_info)(char *buf, char **start, off_t fpos, int length);
EXPORT_SYMBOL(apm_get_info);
/*
* APM event queue management.
*/
static inline int queue_empty(struct apm_queue *q)
{
return q->event_head == q->event_tail;
}
static inline apm_event_t queue_get_event(struct apm_queue *q)
{
q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
return q->events[q->event_tail];
}
static void queue_add_event(struct apm_queue *q, apm_event_t event)
{
q->event_head = (q->event_head + 1) % APM_MAX_EVENTS;
if (q->event_head == q->event_tail) {
static int notified;
if (notified++ == 0)
printk(KERN_ERR "apm: an event queue overflowed\n");
q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
}
q->events[q->event_head] = event;
}
static void queue_event_one_user(struct apm_user *as, apm_event_t event)
{
if (as->suser && as->writer) {
switch (event) {
case APM_SYS_SUSPEND:
case APM_USER_SUSPEND:
/*
* If this user already has a suspend pending,
* don't queue another one.
*/
if (as->suspend_state != SUSPEND_NONE)
return;
as->suspend_state = SUSPEND_PENDING;
suspends_pending++;
break;
}
}
queue_add_event(&as->queue, event);
}
static void queue_event(apm_event_t event, struct apm_user *sender)
{
struct apm_user *as;
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list)
if (as != sender && as->reader)
queue_event_one_user(as, event);
up_read(&user_list_lock);
wake_up_interruptible(&apm_waitqueue);
}
/**
* apm_queue_event - queue an APM event for kapmd
* @event: APM event
*
* Queue an APM event for kapmd to process and ultimately take the
* appropriate action. Only a subset of events are handled:
* %APM_LOW_BATTERY
* %APM_POWER_STATUS_CHANGE
* %APM_USER_SUSPEND
* %APM_SYS_SUSPEND
* %APM_CRITICAL_SUSPEND
*/
void apm_queue_event(apm_event_t event)
{
spin_lock_irq(&kapmd_queue_lock);
queue_add_event(&kapmd_queue, event);
spin_unlock_irq(&kapmd_queue_lock);
wake_up_interruptible(&kapmd_wait);
}
EXPORT_SYMBOL(apm_queue_event);
static void apm_suspend(void)
{
struct apm_user *as;
int err;
apm_suspended = 1;
err = pm_suspend(PM_SUSPEND_MEM);
/*
* Anyone on the APM queues will think we're still suspended.
* Send a message so everyone knows we're now awake again.
*/
queue_event(APM_NORMAL_RESUME, NULL);
/*
* Finally, wake up anyone who is sleeping on the suspend.
*/
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list) {
as->suspend_result = err;
as->suspend_state = SUSPEND_DONE;
}
up_read(&user_list_lock);
wake_up(&apm_suspend_waitqueue);
apm_suspended = 0;
}
static ssize_t apm_read(struct file *fp, char __user *buf,
size_t count, loff_t *ppos)
{
struct apm_user *as = fp->private_data;
apm_event_t event;
int i = count, ret = 0;
if (count < sizeof(apm_event_t))
return -EINVAL;
if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK)
return -EAGAIN;
wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue));
while ((i >= sizeof(event)) && !queue_empty(&as->queue)) {
event = queue_get_event(&as->queue);
ret = -EFAULT;
if (copy_to_user(buf, &event, sizeof(event)))
break;
if (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND)
as->suspend_state = SUSPEND_READ;
buf += sizeof(event);
i -= sizeof(event);
}
if (i < count)
ret = count - i;
return ret;
}
static unsigned int apm_poll(struct file *fp, poll_table * wait)
{
struct apm_user *as = fp->private_data;
poll_wait(fp, &apm_waitqueue, wait);
return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM;
}
/*
* apm_ioctl - handle APM ioctl
*
* APM_IOC_SUSPEND
* This IOCTL is overloaded, and performs two functions. It is used to:
* - initiate a suspend
* - acknowledge a suspend read from /dev/apm_bios.
* Only when everyone who has opened /dev/apm_bios with write permission
* has acknowledge does the actual suspend happen.
*/
static int
apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg)
{
struct apm_user *as = filp->private_data;
unsigned long flags;
int err = -EINVAL;
if (!as->suser || !as->writer)
return -EPERM;
switch (cmd) {
case APM_IOC_SUSPEND:
as->suspend_result = -EINTR;
if (as->suspend_state == SUSPEND_READ) {
/*
* If we read a suspend command from /dev/apm_bios,
* then the corresponding APM_IOC_SUSPEND ioctl is
* interpreted as an acknowledge.
*/
as->suspend_state = SUSPEND_ACKED;
suspends_pending--;
} else {
/*
* Otherwise it is a request to suspend the system.
* Queue an event for all readers, and expect an
* acknowledge from all writers who haven't already
* acknowledged.
*/
queue_event(APM_USER_SUSPEND, as);
}
/*
* If there are no further acknowledges required, suspend
* the system.
*/
if (suspends_pending == 0)
apm_suspend();
/*
* Wait for the suspend/resume to complete. If there are
* pending acknowledges, we wait here for them.
*
* Note that we need to ensure that the PM subsystem does
* not kick us out of the wait when it suspends the threads.
*/
flags = current->flags;
current->flags |= PF_NOFREEZE;
/*
* Note: do not allow a thread which is acking the suspend
* to escape until the resume is complete.
*/
if (as->suspend_state == SUSPEND_ACKED)
wait_event(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
else
wait_event_interruptible(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
current->flags = flags;
err = as->suspend_result;
as->suspend_state = SUSPEND_NONE;
break;
}
return err;
}
static int apm_release(struct inode * inode, struct file * filp)
{
struct apm_user *as = filp->private_data;
filp->private_data = NULL;
down_write(&user_list_lock);
list_del(&as->list);
up_write(&user_list_lock);
/*
* We are now unhooked from the chain. As far as new
* events are concerned, we no longer exist. However, we
* need to balance suspends_pending, which means the
* possibility of sleeping.
*/
if (as->suspend_state != SUSPEND_NONE) {
suspends_pending -= 1;
if (suspends_pending == 0)
apm_suspend();
}
kfree(as);
return 0;
}
static int apm_open(struct inode * inode, struct file * filp)
{
struct apm_user *as;
as = kzalloc(sizeof(*as), GFP_KERNEL);
if (as) {
/*
* XXX - this is a tiny bit broken, when we consider BSD
* process accounting. If the device is opened by root, we
* instantly flag that we used superuser privs. Who knows,
* we might close the device immediately without doing a
* privileged operation -- cevans
*/
as->suser = capable(CAP_SYS_ADMIN);
as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
down_write(&user_list_lock);
list_add(&as->list, &apm_user_list);
up_write(&user_list_lock);
filp->private_data = as;
}
return as ? 0 : -ENOMEM;
}
static struct file_operations apm_bios_fops = {
.owner = THIS_MODULE,
.read = apm_read,
.poll = apm_poll,
.ioctl = apm_ioctl,
.open = apm_open,
.release = apm_release,
};
static struct miscdevice apm_device = {
.minor = APM_MINOR_DEV,
.name = "apm_bios",
.fops = &apm_bios_fops
};
#ifdef CONFIG_PROC_FS
/*
* Arguments, with symbols from linux/apm_bios.h.
*
* 0) Linux driver version (this will change if format changes)
* 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2.
* 2) APM flags from APM Installation Check (0x00):
* bit 0: APM_16_BIT_SUPPORT
* bit 1: APM_32_BIT_SUPPORT
* bit 2: APM_IDLE_SLOWS_CLOCK
* bit 3: APM_BIOS_DISABLED
* bit 4: APM_BIOS_DISENGAGED
* 3) AC line status
* 0x00: Off-line
* 0x01: On-line
* 0x02: On backup power (BIOS >= 1.1 only)
* 0xff: Unknown
* 4) Battery status
* 0x00: High
* 0x01: Low
* 0x02: Critical
* 0x03: Charging
* 0x04: Selected battery not present (BIOS >= 1.2 only)
* 0xff: Unknown
* 5) Battery flag
* bit 0: High
* bit 1: Low
* bit 2: Critical
* bit 3: Charging
* bit 7: No system battery
* 0xff: Unknown
* 6) Remaining battery life (percentage of charge):
* 0-100: valid
* -1: Unknown
* 7) Remaining battery life (time units):
* Number of remaining minutes or seconds
* -1: Unknown
* 8) min = minutes; sec = seconds
*/
static int apm_read_proc(char *buf, char **start, off_t fpos, int length)
{
if (likely(apm_get_info))
return apm_get_info(buf, start, fpos, length);
return -EINVAL;
}
#endif
static int kapmd(void *arg)
{
daemonize("kapmd");
current->flags |= PF_NOFREEZE;
do {
apm_event_t event;
wait_event_interruptible(kapmd_wait,
!queue_empty(&kapmd_queue) || !pm_active);
if (!pm_active)
break;
spin_lock_irq(&kapmd_queue_lock);
event = 0;
if (!queue_empty(&kapmd_queue))
event = queue_get_event(&kapmd_queue);
spin_unlock_irq(&kapmd_queue_lock);
switch (event) {
case 0:
break;
case APM_LOW_BATTERY:
case APM_POWER_STATUS_CHANGE:
queue_event(event, NULL);
break;
case APM_USER_SUSPEND:
case APM_SYS_SUSPEND:
queue_event(event, NULL);
if (suspends_pending == 0)
apm_suspend();
break;
case APM_CRITICAL_SUSPEND:
apm_suspend();
break;
}
} while (1);
complete_and_exit(&kapmd_exit, 0);
}
static int __init apm_init(void)
{
int ret;
pm_active = 1;
ret = kernel_thread(kapmd, NULL, CLONE_KERNEL);
if (unlikely(ret < 0)) {
pm_active = 0;
return ret;
}
create_proc_info_entry("apm", 0, NULL, apm_read_proc);
ret = misc_register(&apm_device);
if (unlikely(ret != 0)) {
remove_proc_entry("apm", NULL);
pm_active = 0;
wake_up(&kapmd_wait);
wait_for_completion(&kapmd_exit);
}
return ret;
}
static void __exit apm_exit(void)
{
misc_deregister(&apm_device);
remove_proc_entry("apm", NULL);
pm_active = 0;
wake_up(&kapmd_wait);
wait_for_completion(&kapmd_exit);
}
module_init(apm_init);
module_exit(apm_exit);
MODULE_AUTHOR("Stephen Rothwell, Andriy Skulysh");
MODULE_DESCRIPTION("Advanced Power Management");
MODULE_LICENSE("GPL");

2
drivers/char/Makefile
View file

@ -60,6 +60,8 @@ obj-$(CONFIG_BRIQ_PANEL) += briq_panel.o
obj-$(CONFIG_PRINTER) += lp.o
obj-$(CONFIG_TIPAR) += tipar.o
obj-$(CONFIG_APM_EMULATION) += apm-emulation.o
obj-$(CONFIG_DTLK) += dtlk.o
obj-$(CONFIG_R3964) += n_r3964.o
obj-$(CONFIG_APPLICOM) += applicom.o

8
arch/arm/kernel/apm.c → drivers/char/apm-emulation.c
View file

@ -1,5 +1,5 @@
/*
* bios-less APM driver for ARM Linux
* bios-less APM driver for ARM Linux
* Jamey Hicks <jamey@crl.dec.com>
* adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com)
*
@ -19,6 +19,7 @@
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/apm-emulation.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/list.h>
@ -27,7 +28,6 @@
#include <linux/kthread.h>
#include <linux/delay.h>
#include <asm/apm.h> /* apm_power_info */
#include <asm/system.h>
/*
@ -225,7 +225,7 @@ static void apm_suspend(void)
list_for_each_entry(as, &apm_user_list, list) {
if (as->suspend_state == SUSPEND_WAIT ||
as->suspend_state == SUSPEND_ACKED) {
as->suspend_result = err;
as->suspend_result = err;
as->suspend_state = SUSPEND_DONE;
}
}
@ -529,7 +529,7 @@ static int apm_get_info(char *buf, char **start, off_t fpos, int length)
info.battery_flag, info.battery_life,
info.time, units);
return ret;
return ret;
}
#endif

64
include/asm-arm/apm.h
View file

@ -1,64 +0,0 @@
/* -*- linux-c -*-
*
* (C) 2003 zecke@handhelds.org
*
* GPL version 2
*
* based on arch/arm/kernel/apm.c
* factor out the information needed by architectures to provide
* apm status
*
*
*/
#ifndef ARM_ASM_SA1100_APM_H
#define ARM_ASM_SA1100_APM_H
#include <linux/apm_bios.h>
/*
* This structure gets filled in by the machine specific 'get_power_status'
* implementation. Any fields which are not set default to a safe value.
*/
struct apm_power_info {
unsigned char ac_line_status;
#define APM_AC_OFFLINE 0
#define APM_AC_ONLINE 1
#define APM_AC_BACKUP 2
#define APM_AC_UNKNOWN 0xff
unsigned char battery_status;
#define APM_BATTERY_STATUS_HIGH 0
#define APM_BATTERY_STATUS_LOW 1
#define APM_BATTERY_STATUS_CRITICAL 2
#define APM_BATTERY_STATUS_CHARGING 3
#define APM_BATTERY_STATUS_NOT_PRESENT 4
#define APM_BATTERY_STATUS_UNKNOWN 0xff
unsigned char battery_flag;
#define APM_BATTERY_FLAG_HIGH (1 << 0)
#define APM_BATTERY_FLAG_LOW (1 << 1)
#define APM_BATTERY_FLAG_CRITICAL (1 << 2)
#define APM_BATTERY_FLAG_CHARGING (1 << 3)
#define APM_BATTERY_FLAG_NOT_PRESENT (1 << 7)
#define APM_BATTERY_FLAG_UNKNOWN 0xff
int battery_life;
int time;
int units;
#define APM_UNITS_MINS 0
#define APM_UNITS_SECS 1
#define APM_UNITS_UNKNOWN -1
};
/*
* This allows machines to provide their own "apm get power status" function.
*/
extern void (*apm_get_power_status)(struct apm_power_info *);
/*
* Queue an event (APM_SYS_SUSPEND or APM_CRITICAL_SUSPEND)
*/
void apm_queue_event(apm_event_t event);
#endif

46
include/asm-sh/apm.h
View file

@ -1,46 +0,0 @@
/*
* Copyright 2006 (c) Andriy Skulysh <askulysh@gmail.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
*/
#ifndef __ASM_SH_APM_H
#define __ASM_SH_APM_H
#define APM_AC_OFFLINE 0
#define APM_AC_ONLINE 1
#define APM_AC_BACKUP 2
#define APM_AC_UNKNOWN 0xff
#define APM_BATTERY_STATUS_HIGH 0
#define APM_BATTERY_STATUS_LOW 1
#define APM_BATTERY_STATUS_CRITICAL 2
#define APM_BATTERY_STATUS_CHARGING 3
#define APM_BATTERY_STATUS_NOT_PRESENT 4
#define APM_BATTERY_STATUS_UNKNOWN 0xff
#define APM_BATTERY_LIFE_UNKNOWN 0xFFFF
#define APM_BATTERY_LIFE_MINUTES 0x8000
#define APM_BATTERY_LIFE_VALUE_MASK 0x7FFF
#define APM_BATTERY_FLAG_HIGH (1 << 0)
#define APM_BATTERY_FLAG_LOW (1 << 1)
#define APM_BATTERY_FLAG_CRITICAL (1 << 2)
#define APM_BATTERY_FLAG_CHARGING (1 << 3)
#define APM_BATTERY_FLAG_NOT_PRESENT (1 << 7)
#define APM_BATTERY_FLAG_UNKNOWN 0xff
#define APM_UNITS_MINS 0
#define APM_UNITS_SECS 1
#define APM_UNITS_UNKNOWN -1
extern int (*apm_get_info)(char *buf, char **start, off_t fpos, int length);
extern int apm_suspended;
void apm_queue_event(apm_event_t event);
#endif

8
include/asm-mips/apm.h → include/linux/apm-emulation.h
View file

@ -7,11 +7,9 @@
* based on arch/arm/kernel/apm.c
* factor out the information needed by architectures to provide
* apm status
*
*
*/
#ifndef MIPS_ASM_SA1100_APM_H
#define MIPS_ASM_SA1100_APM_H
#ifndef __LINUX_APM_EMULATION_H
#define __LINUX_APM_EMULATION_H
#include <linux/apm_bios.h>
@ -61,4 +59,4 @@ extern void (*apm_get_power_status)(struct apm_power_info *);
*/
void apm_queue_event(apm_event_t event);
#endif
#endif /* __LINUX_APM_EMULATION_H */

26
kernel/power/Kconfig
View file

@ -131,3 +131,29 @@ config SUSPEND_SMP
bool
depends on HOTPLUG_CPU && X86 && PM
default y
config APM_EMULATION
tristate "Advanced Power Management Emulation"
depends on PM && SYS_SUPPORTS_APM_EMULATION
help
APM is a BIOS specification for saving power using several different
techniques. This is mostly useful for battery powered laptops with
APM compliant BIOSes. If you say Y here, the system time will be
reset after a RESUME operation, the /proc/apm device will provide
battery status information, and user-space programs will receive
notification of APM "events" (e.g. battery status change).
In order to use APM, you will need supporting software. For location
and more information, read <file:Documentation/pm.txt> and the
Battery Powered Linux mini-HOWTO, available from
<http://www.tldp.org/docs.html#howto>.
This driver does not spin down disk drives (see the hdparm(8)
manpage ("man 8 hdparm") for that), and it doesn't turn off
VESA-compliant "green" monitors.
Generally, if you don't have a battery in your machine, there isn't
much point in using this driver and you should say N. If you get
random kernel OOPSes or reboots that don't seem to be related to
anything, try disabling/enabling this option (or disabling/enabling
APM in your BIOS).