linux-toradex.git/kernel/power/suspend.c, branch v3.3.5

PM / Sleep: Move disabling of usermode helpers to the freezer

2012-04-13T16:13:54+00:00

commit 1e73203cd1157a03facc41ffb54050f5b28e55bd upstream.

The core suspend/hibernation code calls usermodehelper_disable() to
avoid race conditions between the freezer and the starting of
usermode helpers and each code path has to do that on its own.
However, it is always called right before freeze_processes()
and usermodehelper_enable() is always called right after
thaw_processes().  For this reason, to avoid code duplication and
to make the connection between usermodehelper_disable() and the
freezer more visible, make freeze_processes() call it and remove the
direct usermodehelper_disable() and usermodehelper_enable() calls
from all suspend/hibernation code paths.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

PM / Sleep: Replace mutex_[un]lock(&pm_mutex) with [un]lock_system_sleep()

2011-12-08T22:22:29+00:00

Using [un]lock_system_sleep() is safer than directly using mutex_[un]lock()
on 'pm_mutex', since the latter could lead to freezing failures. Hence convert
all the present users of mutex_[un]lock(&pm_mutex) to use these safe APIs
instead.

Suggested-by: Tejun Heo 
Signed-off-by: Srivatsa S. Bhat 
Reviewed-by: Simon Horman 
Signed-off-by: Rafael J. Wysocki

freezer: clean up freeze_processes() failure path

2011-11-21T20:32:24+00:00

freeze_processes() failure path is rather messy.  Freezing is canceled
for workqueues and tasks which aren't frozen yet but frozen tasks are
left alone and should be thawed by the caller and of course some
callers (xen and kexec) didn't do it.

This patch updates __thaw_task() to handle cancelation correctly and
makes freeze_processes() and freeze_kernel_threads() call
thaw_processes() on failure instead so that the system is fully thawed
on failure.  Unnecessary [suspend_]thaw_processes() calls are removed
from kernel/power/hibernate.c, suspend.c and user.c.

While at it, restructure error checking if clause in suspend_prepare()
to be less weird.

-v2: Srivatsa spotted missing removal of suspend_thaw_processes() in
     suspend_prepare() and error in commit message.  Updated.

Signed-off-by: Tejun Heo 
Acked-by: Srivatsa S. Bhat

kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure

2011-10-31T23:30:05+00:00

These files were getting  via an implicit non-obvious
path, but we want to crush those out of existence since they cost
time during compiles of processing thousands of lines of headers
for no reason.  Give them the lightweight header that just contains
the EXPORT_SYMBOL infrastructure.

Signed-off-by: Paul Gortmaker

kernel: fix several implicit usasges of kmod.h

2011-10-31T13:20:12+00:00

These files were implicitly relying on  coming in via
module.h, as without it we get things like:

kernel/power/suspend.c:100: error: implicit declaration of function ‘usermodehelper_disable’
kernel/power/suspend.c:109: error: implicit declaration of function ‘usermodehelper_enable’
kernel/power/user.c:254: error: implicit declaration of function ‘usermodehelper_disable’
kernel/power/user.c:261: error: implicit declaration of function ‘usermodehelper_enable’

kernel/sys.c:317: error: implicit declaration of function ‘usermodehelper_disable’
kernel/sys.c:1816: error: implicit declaration of function ‘call_usermodehelper_setup’
kernel/sys.c:1822: error: implicit declaration of function ‘call_usermodehelper_setfns’
kernel/sys.c:1824: error: implicit declaration of function ‘call_usermodehelper_exec’

Signed-off-by: Paul Gortmaker

PM / Suspend: Off by one in pm_suspend()

2011-10-16T21:27:46+00:00

In enter_state() we use "state" as an offset for the pm_states[]
array.  The pm_states[] array only has PM_SUSPEND_MAX elements so
this test is off by one.

Signed-off-by: Dan Carpenter 
Signed-off-by: Rafael J. Wysocki 
Cc: stable@kernel.org

PM / Suspend: Add statistics debugfs file for suspend to RAM

2011-10-16T21:27:45+00:00

Record S3 failure time about each reason and the latest two failed
devices' names in S3 progress.
We can check it through 'suspend_stats' entry in debugfs.

The motivation of the patch:

We are enabling power features on Medfield. Comparing with PC/notebook,
a mobile enters/exits suspend-2-ram (we call it s3 on Medfield) far
more frequently. If it can't enter suspend-2-ram in time, the power
might be used up soon.

We often find sometimes, a device suspend fails. Then, system retries
s3 over and over again. As display is off, testers and developers
don't know what happens.

Some testers and developers complain they don't know if system
tries suspend-2-ram, and what device fails to suspend. They need
such info for a quick check. The patch adds suspend_stats under
debugfs for users to check suspend to RAM statistics quickly.

If not using this patch, we have other methods to get info about
what device fails. One is to turn on  CONFIG_PM_DEBUG, but users
would get too much info and testers need recompile the system.

In addition, dynamic debug is another good tool to dump debug info.
But it still doesn't match our utilization scenario closely.
1) user need write a user space parser to process the syslog output;
2) Our testing scenario is we leave the mobile for at least hours.
   Then, check its status. No serial console available during the
   testing. One is because console would be suspended, and the other
   is serial console connecting with spi or HSU devices would consume
   power. These devices are powered off at suspend-2-ram.

Signed-off-by: ShuoX Liu 
Signed-off-by: Rafael J. Wysocki

PM / Suspend: Export suspend_set_ops, suspend_valid_only_mem

2011-07-15T21:58:19+00:00

Some platforms wish to implement their PM core suspend code as
modules.  To do so, these functions need to be exported to modules.

[rjw: Replaced EXPORT_SYMBOL with EXPORT_SYMBOL_GPL]

Reported-by: Jean Pihet 
Signed-off-by: Kevin Hilman 
Signed-off-by: Rafael J. Wysocki

PM / Suspend: Add .suspend_again() callback to suspend_ops

2011-07-15T21:58:19+00:00

A system or a device may need to control suspend/wakeup events. It may
want to wakeup the system after a predefined amount of time or at a
predefined event decided while entering suspend for polling or delayed
work. Then, it may want to enter suspend again if its predefined wakeup
condition is the only wakeup reason and there is no outstanding events;
thus, it does not wakeup the userspace unnecessary or unnecessary
devices and keeps suspended as long as possible (saving the power).

Enabling a system to wakeup after a specified time can be easily
achieved by using RTC. However, to enter suspend again immediately
without invoking userland and unrelated devices, we need additional
features in the suspend framework.

Such need comes from:

 1. Monitoring a critical device status without interrupts that can
wakeup the system. (in-suspend polling)
 An example is ambient temperature monitoring that needs to shut down
the system or a specific device function if it is too hot or cold. The
temperature of a specific device may be needed to be monitored as well;
e.g., a charger monitors battery temperature in order to stop charging
if overheated.

 2. Execute critical "delayed work" at suspend.
 A driver or a system/board may have a delayed work (or any similar
things) that it wants to execute at the requested time.
 For example, some chargers want to check the battery voltage some
time (e.g., 30 seconds) after the battery is fully charged and the
charger has stopped. Then, the charger restarts charging if the voltage
has dropped more than a threshold, which is smaller than "restart-charger"
voltage, which is a threshold to restart charging regardless of the
time passed.

This patch allows to add "suspend_again" callback at struct
platform_suspend_ops and let the "suspend_again" callback return true if
the system is required to enter suspend again after the current instance
of wakeup. Device-wise suspend_again implemented at dev_pm_ops or
syscore is not done because: a) suspend_again feature is usually under
platform-wise decision and controls the behavior of the whole platform
and b) There are very limited devices related to the usage cases of
suspend_again; chargers and temperature sensors are mentioned so far.

With suspend_again callback registered at struct platform_suspend_ops
suspend_ops in kernel/power/suspend.c with suspend_set_ops by the
platform, the suspend framework tries to enter suspend again by
looping suspend_enter() if suspend_again has returned true and there has
been no errors in the suspending sequence or pending wakeups (by
pm_wakeup_pending).

Tested at Exynos4-NURI.

[rjw: Fixed up kerneldoc comment for suspend_enter().]

Signed-off-by: MyungJoo Ham 
Signed-off-by: Kyungmin Park 
Acked-by: Pavel Machek 
Signed-off-by: Rafael J. Wysocki

Merge branch 'syscore' into for-linus

2011-05-17T21:23:40+00:00

* syscore:
  PM: Remove sysdev suspend, resume and shutdown operations
  PM / PowerPC: Use struct syscore_ops instead of sysdevs for PM
  PM / UNICORE32: Use struct syscore_ops instead of sysdevs for PM
  PM / AVR32: Use struct syscore_ops instead of sysdevs for PM
  PM / Blackfin: Use struct syscore_ops instead of sysdevs for PM
  ARM / Samsung: Use struct syscore_ops for "core" power management
  ARM / PXA: Use struct syscore_ops for "core" power management
  ARM / SA1100: Use struct syscore_ops for "core" power management
  ARM / Integrator: Use struct syscore_ops for core PM
  ARM / OMAP: Use struct syscore_ops for "core" power management
  ARM: Use struct syscore_ops instead of sysdevs for PM in common code