linux-toradex.git/kernel/power/suspend.c, branch v4.4.106

PM / sleep: Add flags to indicate platform firmware involvement

2015-10-14T00:17:33+00:00

There are quite a few cases in which device drivers, bus types or
even the PM core itself may benefit from knowing whether or not
the platform firmware will be involved in the upcoming system power
transition (during system suspend) or whether or not it was involved
in it (during system resume).

For this reason, introduce global system suspend flags that can be
used by the platform code to expose that information for the benefit
of the other parts of the kernel and make the ACPI core set them
as appropriate.

Users of the new flags will be added later.

Signed-off-by: Rafael J. Wysocki

PM / suspend: make sync() on suspend-to-RAM build-time optional

2015-07-31T21:46:05+00:00

The Linux kernel suspend path has traditionally invoked sys_sync()
before freezing user threads.

But sys_sync() can be expensive, and some user-space OS's do not want
the kernel to pay the cost of sys_sync() on every suspend -- preferring
invoke sync() from user-space if/when they want it.

So make sys_sync on suspend build-time optional.

The default is unchanged.

Signed-off-by: Len Brown 
Signed-off-by: Rafael J. Wysocki

PM / sleep: Return -EBUSY from suspend_enter() on wakeup detection

2015-05-19T00:26:56+00:00

If a wakeup source is found to be pending in the last stage of
suspend after syscore suspend, then the machine won't suspend, but
suspend_enter() will return 0.  That is confusing, as wakeup detection
elsewhere causes -EBUSY to be returned from suspend_enter().

To avoid the confusion, make suspend_enter() return -EBUSY in that
case too.

Signed-off-by: Ruchi Kandoi 
[ rjw: Subject and changelog ]
Signed-off-by: Rafael J. Wysocki

PM / sleep: Refine diagnostic messages in enter_state()

2015-05-12T21:45:12+00:00

Some of the system suspend diagnostic messages related to
suspend-to-idle refer to it as "freeze sleep" or "freeze state"
while the others say "suspend-to-idle".  To reduce the possible
confusion that may result from that, refine the former either to
say "suspend to idle" too or to make it clearer that what is printed
is a state string written to /sys/power/state ("mem", "standby",
or "freeze").

Signed-off-by: Rafael J. Wysocki

PM / sleep: add configurable delay for pm_test

2015-02-26T00:21:26+00:00

When CONFIG_PM_DEBUG=y, we provide a sysfs file (/sys/power/pm_test) for
selecting one of a few suspend test modes, where rather than entering a
full suspend state, the kernel will perform some subset of suspend
steps, wait 5 seconds, and then resume back to normal operation.

This mode is useful for (among other things) observing the state of the
system just before entering a sleep mode, for debugging or analysis
purposes. However, a constant 5 second wait is not sufficient for some
sorts of analysis; for example, on an SoC, one might want to use
external tools to probe the power states of various on-chip controllers
or clocks.

This patch turns this 5 second delay into a configurable module
parameter, so users can determine how long to wait in this
pseudo-suspend state before resuming the system.

Example (wait 30 seconds);

  # echo 30 > /sys/module/suspend/parameters/pm_test_delay
  # echo core > /sys/power/pm_test
  # time echo mem  > /sys/power/state
  ...
  [   17.583625] suspend debug: Waiting for 30 second(s).
  ...
  real	0m30.381s
  user	0m0.017s
  sys	0m0.080s

Signed-off-by: Brian Norris 
Acked-by: Pavel Machek 
Reviewed-by: Kevin Cernekee 
Acked-by: Florian Fainelli 
Signed-off-by: Rafael J. Wysocki

PM / sleep: Re-implement suspend-to-idle handling

2015-02-13T22:49:36+00:00

In preparation for adding support for quiescing timers in the final
stage of suspend-to-idle transitions, rework the freeze_enter()
function making the system wait on a wakeup event, the freeze_wake()
function terminating the suspend-to-idle loop and the mechanism by
which deep idle states are entered during suspend-to-idle.

First of all, introduce a simple state machine for suspend-to-idle
and make the code in question use it.

Second, prevent freeze_enter() from losing wakeup events due to race
conditions and ensure that the number of online CPUs won't change
while it is being executed.  In addition to that, make it force
all of the CPUs re-enter the idle loop in case they are in idle
states already (so they can enter deeper idle states if possible).

Next, drop cpuidle_use_deepest_state() and replace use_deepest_state
checks in cpuidle_select() and cpuidle_reflect() with a single
suspend-to-idle state check in cpuidle_idle_call().

Finally, introduce cpuidle_enter_freeze() that will simply find the
deepest idle state available to the given CPU and enter it using
cpuidle_enter().

Signed-off-by: Rafael J. Wysocki 
Acked-by: Peter Zijlstra (Intel)

PM / sleep: Fix entering suspend-to-IDLE if no freeze_oops is set

2014-11-08T21:30:05+00:00

If no freeze_ops is set, trying to enter suspend-to-IDLE will cause a
nice oops in platform_suspend_prepare_late(). Add respective checks to
platform_suspend_prepare_late() and platform_resume_early() functions.

Fixes: a8d46b9e4e48 (ACPI / sleep: Rework the handling of ACPI GPE wakeup ...)
Signed-off-by: Dmitry Eremin-Solenikov 
Signed-off-by: Rafael J. Wysocki

ACPI / sleep: Rework the handling of ACPI GPE wakeup from suspend-to-idle

2014-09-30T19:06:07+00:00

The ACPI GPE wakeup from suspend-to-idle is currently based on using
the IRQF_NO_SUSPEND flag for the ACPI SCI, but that is problematic
for a couple of reasons.  First, in principle the ACPI SCI may be
shared and IRQF_NO_SUSPEND does not really work well with shared
interrupts.  Second, it may require the ACPI subsystem to special-case
the handling of device notifications depending on whether or not
they are received during suspend-to-idle in some places which would
lead to fragile code.  Finally, it's better the handle ACPI wakeup
interrupts consistently with wakeup interrupts from other sources.

For this reason, remove the IRQF_NO_SUSPEND flag from the ACPI SCI
and use enable_irq_wake()/disable_irq_wake() with it instead, which
requires two additional platform hooks to be added to struct
platform_freeze_ops.

Signed-off-by: Rafael J. Wysocki

PM / sleep: Rename platform suspend/resume functions in suspend.c

2014-09-30T19:05:59+00:00

Rename several local functions related to platform handling during
system suspend resume in suspend.c so that their names better
reflect their roles.

Signed-off-by: Rafael J. Wysocki

PM / sleep: Export dpm_suspend_late/noirq() and dpm_resume_early/noirq()

2014-09-30T19:05:59+00:00

Subsequent change sets will add platform-related operations between
dpm_suspend_late() and dpm_suspend_noirq() as well as between
dpm_resume_noirq() and dpm_resume_early() in suspend_enter(), so
export these functions for suspend_enter() to be able to call them
separately and split the invocations of dpm_suspend_end() and
dpm_resume_start() in there accordingly.

Signed-off-by: Rafael J. Wysocki