linux-toradex.git/kernel/power/main.c, branch v5.12-rc8

PM: sleep: Constify static struct attribute_group

2021-02-12T15:46:59+00:00

The only usage of suspend_attr_group is to put its address in an
array of pointers to const attribute_group structs.

Make it const to allow the compiler to put it into read-only memory.

Signed-off-by: Rikard Falkeborn 
Signed-off-by: Rafael J. Wysocki

notifier: Fix broken error handling pattern

2020-09-01T07:58:03+00:00

The current notifiers have the following error handling pattern all
over the place:

	int err, nr;

	err = __foo_notifier_call_chain(&chain, val_up, v, -1, &nr);
	if (err & NOTIFIER_STOP_MASK)
		__foo_notifier_call_chain(&chain, val_down, v, nr-1, NULL)

And aside from the endless repetition thereof, it is broken. Consider
blocking notifiers; both calls take and drop the rwsem, this means
that the notifier list can change in between the two calls, making @nr
meaningless.

Fix this by replacing all the __foo_notifier_call_chain() functions
with foo_notifier_call_chain_robust() that embeds the above pattern,
but ensures it is inside a single lock region.

Note: I switched atomic_notifier_call_chain_robust() to use
      the spinlock, since RCU cannot provide the guarantee
      required for the recovery.

Note: software_resume() error handling was broken afaict.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20200818135804.325626653@infradead.org

PM: sleep: Add pm_debug_messages kernel command line option

2020-04-02T13:29:56+00:00

Debug messages from the system suspend/hibernation infrastructure
are disabled by default, and can only be enabled after the system
has boot up via /sys/power/pm_debug_messages.

This makes the hibernation resume hard to track as it involves system
boot up across hibernation.  There's no chance for software_resume()
to track the resume process, for example.

Add a kernel command line option to set pm_debug_messages during
boot up.

Signed-off-by: Chen Yu 
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki

PM: suspend: Add sysfs attribute to control the "sync on suspend" behavior

2020-01-16T20:47:03+00:00

The sysfs attribute `/sys/power/sync_on_suspend` controls, whether or not
filesystems are synced by the kernel before system suspend.

Congruously, the behaviour of build-time switch CONFIG_SUSPEND_SKIP_SYNC
is slightly changed: It now defines the run-tim default for the new sysfs
attribute `/sys/power/sync_on_suspend`.

The run-time attribute is added because the existing corresponding
build-time Kconfig flag for (`CONFIG_SUSPEND_SKIP_SYNC`) is not flexible
enough. E.g. Linux distributions that provide pre-compiled kernels
usually want to stick with the default (sync filesystems before suspend)
but under special conditions this needs to be changed.

One example for such a special condition is user-space handling of
suspending block devices (e.g. using `cryptsetup luksSuspend` or `dmsetup
suspend`) before system suspend. The Kernel trying to sync filesystems
after the underlying block device already got suspended obviously leads
to dead-locks. Be aware that you have to take care of the filesystem sync
yourself before suspending the system in those scenarios.

Signed-off-by: Jonas Meurer 
Signed-off-by: Rafael J. Wysocki

PM: sleep: include for pm_wq

2019-10-10T09:11:56+00:00

Include the  for the definition of
pm_wq to avoid the following warning:

kernel/power/main.c:890:25: warning: symbol 'pm_wq' was not declared. Should it be static?

Signed-off-by: Ben Dooks 
Signed-off-by: Rafael J. Wysocki

PM: sleep: Replace strncmp() with str_has_prefix()

2019-08-16T12:18:53+00:00

Use str_has_prefix() instead of strncmp() which is less
straightforward in decode_state().

Signed-off-by: Chuhong Yuan 
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki

PM/sleep: Expose suspend stats in sysfs

2019-08-05T10:03:18+00:00

Userspace can get suspend stats from the suspend stats debugfs node.
Since debugfs doesn't have stable ABI, expose suspend stats in
sysfs under /sys/power/suspend_stats.

Signed-off-by: Kalesh Singh 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Rafael J. Wysocki

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428

2019-06-05T15:37:16+00:00

Based on 1 normalized pattern(s):

  this file is released under the gplv2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 68 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Armijn Hemel 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190114.292346262@linutronix.de
Signed-off-by: Greg Kroah-Hartman

PM / sleep: Measure the time of filesystems syncing

2019-04-02T08:53:19+00:00

Measure the filesystems sync time during system sleep more precisely.

Among other things, this allows the pr_cont() to be dropped from
ksys_sync_helper() and makes automatic system suspend and hibernation
profiling somewhat more straightforward.

Signed-off-by: Harry Pan 
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki

PM / sleep: Refactor filesystems sync to reduce duplication

2019-04-02T08:53:19+00:00

Create a common helper to sync filesystems for system suspend and
hibernation.

Signed-off-by: Harry Pan 
Acked-by: Pavel Machek 
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki