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rework pm_ops pm_disk_mode, kill misuse

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This patch series cleans up some misconceptions about pm_ops.  Some users of
the pm_ops structure attempt to use it to stop the user from entering suspend
to disk, this, however, is not possible since the user can always use
"shutdown" in /sys/power/disk and then the pm_ops are never invoked.  Also,
platforms that don't support suspend to disk simply should not allow
configuring SOFTWARE_SUSPEND (read the help text on it, it only selects
suspend to disk and nothing else, all the other stuff depends on PM).

The pm_ops structure is actually intended to provide a way to enter
platform-defined sleep states (currently supported states are "standby" and
"mem" (suspend to ram)) and additionally (if SOFTWARE_SUSPEND is configured)
allows a platform to support a platform specific way to enter low-power mode
once everything has been saved to disk.  This is currently only used by ACPI
(S4).

This patch:

The pm_ops.pm_disk_mode is used in totally bogus ways since nobody really
seems to understand what it actually does.

This patch clarifies the pm_disk_mode description.

It also removes all the arm and sh users that think they can veto suspend to
disk via pm_ops; not so since the user can always do echo shutdown >
/sys/power/disk, they need to find a better way involving Kconfig or such.

ACPI is the only user left with a non-zero pm_disk_mode.

The patch also sets the default mode to shutdown again, but when a new pm_ops
is registered its pm_disk_mode is selected as default, that way the default
stays for ACPI where it is apparently required.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: David Brownell <david-b@pacbell.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: <linux-pm@lists.linux-foundation.org>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Greg KH <greg@kroah.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Berg 2007-04-30 15:09:51 -07:00 • committed by Linus Torvalds
parent 1173a729fc
commit fe0c935a6c
11 changed files with 56 additions and 64 deletions
Download patch file Download diff file Expand all files Collapse all files

60
kernel/power/disk.c
View file

@ -39,7 +39,13 @@ static inline int platform_prepare(void)
{
int error = 0;
if (pm_disk_mode == PM_DISK_PLATFORM) {
switch (pm_disk_mode) {
case PM_DISK_TEST:
case PM_DISK_TESTPROC:
case PM_DISK_SHUTDOWN:
case PM_DISK_REBOOT:
break;
default:
if (pm_ops && pm_ops->prepare)
error = pm_ops->prepare(PM_SUSPEND_DISK);
}
@ -48,40 +54,48 @@ static inline int platform_prepare(void)
/**
* power_down - Shut machine down for hibernate.
* @mode: Suspend-to-disk mode
*
* Use the platform driver, if configured so, and return gracefully if it
* fails.
* Otherwise, try to power off and reboot. If they fail, halt the machine,
* there ain't no turning back.
* Use the platform driver, if configured so; otherwise try
* to power off or reboot.
*/
static void power_down(suspend_disk_method_t mode)
static void power_down(void)
{
switch(mode) {
case PM_DISK_PLATFORM:
if (pm_ops && pm_ops->enter) {
kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
pm_ops->enter(PM_SUSPEND_DISK);
break;
}
switch (pm_disk_mode) {
case PM_DISK_TEST:
case PM_DISK_TESTPROC:
break;
case PM_DISK_SHUTDOWN:
kernel_power_off();
break;
case PM_DISK_REBOOT:
kernel_restart(NULL);
break;
default:
if (pm_ops && pm_ops->enter) {
kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
pm_ops->enter(PM_SUSPEND_DISK);
break;
}
}
kernel_halt();
/* Valid image is on the disk, if we continue we risk serious data corruption
after resume. */
/*
* Valid image is on the disk, if we continue we risk serious data
* corruption after resume.
*/
printk(KERN_CRIT "Please power me down manually\n");
while(1);
}
static inline void platform_finish(void)
{
if (pm_disk_mode == PM_DISK_PLATFORM) {
switch (pm_disk_mode) {
case PM_DISK_TEST:
case PM_DISK_TESTPROC:
case PM_DISK_SHUTDOWN:
case PM_DISK_REBOOT:
break;
default:
if (pm_ops && pm_ops->finish)
pm_ops->finish(PM_SUSPEND_DISK);
}
@ -166,7 +180,7 @@ int pm_suspend_disk(void)
pr_debug("PM: writing image.\n");
error = swsusp_write();
if (!error)
power_down(pm_disk_mode);
power_down();
else {
swsusp_free();
goto Thaw;
@ -338,10 +352,14 @@ static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
}
}
if (mode) {
if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT ||
mode == PM_DISK_TEST || mode == PM_DISK_TESTPROC) {
switch (mode) {
case PM_DISK_SHUTDOWN:
case PM_DISK_REBOOT:
case PM_DISK_TEST:
case PM_DISK_TESTPROC:
pm_disk_mode = mode;
} else {
break;
default:
if (pm_ops && pm_ops->enter &&
(mode == pm_ops->pm_disk_mode))
pm_disk_mode = mode;

6
kernel/power/main.c
View file

@ -30,7 +30,7 @@
DEFINE_MUTEX(pm_mutex);
struct pm_ops *pm_ops;
suspend_disk_method_t pm_disk_mode = PM_DISK_PLATFORM;
suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
/**
* pm_set_ops - Set the global power method table.
@ -41,6 +41,10 @@ void pm_set_ops(struct pm_ops * ops)
{
mutex_lock(&pm_mutex);
pm_ops = ops;
if (ops && ops->pm_disk_mode != PM_DISK_INVALID) {
pm_disk_mode = ops->pm_disk_mode;
} else
pm_disk_mode = PM_DISK_SHUTDOWN;
mutex_unlock(&pm_mutex);
}