linux-stable.git/include/linux/pm.h, branch v5.18.3

PM: sleep: Add device name to suspend_report_result()

2022-03-08T18:57:01+00:00

Currently, suspend_report_result() prints only function information.

If any driver uses a common PM function, nobody knows who exactly
called the failing function.

A device pinter is needed to recognize the failing device.

For example:

 PM: dpm_run_callback(): pnp_bus_suspend+0x0/0x10 returns 0
 PM: dpm_run_callback(): pci_pm_suspend+0x0/0x150 returns 0

become after the change:

 serial 00:05: PM: dpm_run_callback(): pnp_bus_suspend+0x0/0x10 returns 0
 pci 0000:00:01.3: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x150 returns 0

Signed-off-by: Youngjin Jang 
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki

PM: runtime: Add DEFINE_RUNTIME_DEV_PM_OPS() macro

2022-01-12T18:59:05+00:00

A lot of drivers create a dev_pm_ops struct with the system sleep
suspend/resume callbacks set to pm_runtime_force_suspend() and
pm_runtime_force_resume().

These drivers can now use the DEFINE_RUNTIME_DEV_PM_OPS() macro, which
will use pm_runtime_force_{suspend,resume}() as the system sleep
callbacks, while having the same dead code removal characteristic that
is already provided by DEFINE_SIMPLE_DEV_PM_OPS().

Signed-off-by: Paul Cercueil 
Acked-by: Jonathan Cameron 
Reviewed-by: Ulf Hansson 
Signed-off-by: Rafael J. Wysocki

PM: core: Add EXPORT[_GPL]_SIMPLE_DEV_PM_OPS macros

2022-01-12T18:59:05+00:00

These macros are defined conditionally, according to CONFIG_PM:
- if CONFIG_PM is enabled, these macros resolve to
  DEFINE_SIMPLE_DEV_PM_OPS(), and the dev_pm_ops symbol will be
  exported.

- if CONFIG_PM is disabled, these macros will result in a dummy static
  dev_pm_ops to be created with the __maybe_unused flag. The dev_pm_ops
  will then be discarded by the compiler, along with the provided
  callback functions if they are not used anywhere else.

In the second case, the symbol is not exported, which should be
perfectly fine - users of the symbol should all use the pm_ptr() or
pm_sleep_ptr() macro, so the dev_pm_ops marked as "extern" in the
client's code will never be accessed.

Signed-off-by: Paul Cercueil 
Acked-by: Jonathan Cameron 
Reviewed-by: Ulf Hansson 
Signed-off-by: Rafael J. Wysocki

PM: core: Remove static qualifier in DEFINE_SIMPLE_DEV_PM_OPS macro

2022-01-12T18:59:05+00:00

Keep this macro in line with the other ones. This makes it possible to
use them in the cases where the underlying dev_pm_ops structure is
exported.

Restore the "static" qualifier in the two drivers where the
DEFINE_SIMPLE_DEV_PM_OPS macro was used.

Signed-off-by: Paul Cercueil 
Acked-by: Jonathan Cameron 
Reviewed-by: Ulf Hansson 
Signed-off-by: Rafael J. Wysocki

PM: core: Remove DEFINE_UNIVERSAL_DEV_PM_OPS() macro

2022-01-12T18:59:05+00:00

The deprecated UNIVERSAL_DEV_PM_OPS() macro uses the provided callbacks
for both runtime PM and system sleep, which is very likely to be a
mistake, as a system sleep can be triggered while a given device is
already PM-suspended, which would cause the suspend callback to be
called twice.

The amount of users of UNIVERSAL_DEV_PM_OPS() is also tiny (16
occurences) compared to the number of places where
SET_SYSTEM_SLEEP_PM_OPS() is used with pm_runtime_force_suspend() and
pm_runtime_force_resume(), which makes me think that none of these cases
are actually valid.

As the new macro DEFINE_UNIVERSAL_DEV_PM_OPS() which was introduced to
replace UNIVERSAL_DEV_PM_OPS() is currently unused, remove it before
someone starts to use it in yet another invalid case.

Signed-off-by: Paul Cercueil 
Acked-by: Jonathan Cameron 
Reviewed-by: Ulf Hansson 
Signed-off-by: Rafael J. Wysocki

PM: runtime: Capture device status before disabling runtime PM

2021-12-17T15:16:40+00:00

In some cases (for example, during system-wide suspend and resume of
devices) it is useful to know whether or not runtime PM has ever been
enabled for a given device and, if so, what the runtime PM status of
it had been right before runtime PM was disabled for it last time.

For this reason, introduce a new struct dev_pm_info field called
last_status that will be used for capturing the runtime PM status of
the device when its power.disable_depth counter changes from 0 to 1.

The new field will be set to RPM_INVALID to start with and whenever
power.disable_depth changes from 1 to 0, so it will be valid only
when runtime PM of the device is currently disabled, but it has been
enabled at least once.

Immediately use power.last_status in rpm_resume() to make it handle
the case when PM runtime is disabled for the device, but its runtime
PM status is RPM_ACTIVE more consistently.  Namely, make it return 1
if power.last_status is also equal to RPM_ACTIVE in that case (the
idea being that if the status was RPM_ACTIVE last time when
power.disable_depth was changing from 0 to 1 and it is still
RPM_ACTIVE, it can be assumed to reflect what happened to the device
last time when it was using runtime PM) and -EACCES otherwise.

Update the documentation to provide a description of last_status and
change the description of pm_runtime_resume() in it to reflect the
new behavior of rpm_active().

While at it, rearrange the code in pm_runtime_enable() to be more
straightforward and replace the WARN() macro in it with a pr_warn()
invocation which is less disruptive.

Link: https://lore.kernel.org/linux-pm/20211026222626.39222-1-ulf.hansson@linaro.org/t/#u
Reviewed-by: Ulf Hansson 
Signed-off-by: Rafael J. Wysocki

PM: core: Add new *_PM_OPS macros, deprecate old ones

2021-12-17T15:04:14+00:00

This commit introduces the following macros:

SYSTEM_SLEEP_PM_OPS()
LATE_SYSTEM_SLEEP_PM_OPS()
NOIRQ_SYSTEM_SLEEP_PM_OPS()
RUNTIME_PM_OPS()

These new macros are very similar to their SET_*_PM_OPS() equivalent.
They however differ in the fact that the callbacks they set will always
be seen as referenced by the compiler. This means that the callback
functions don't need to be wrapped with a #ifdef CONFIG_PM guard, or
tagged with __maybe_unused, to prevent the compiler from complaining
about unused static symbols. The compiler will then simply evaluate at
compile time whether or not these symbols are dead code.

The callbacks that are only useful with CONFIG_PM_SLEEP is enabled, are
now also wrapped with a new pm_sleep_ptr() macro, which is inspired from
pm_ptr(). This is needed for drivers that use different callbacks for
sleep and runtime PM, to handle the case where CONFIG_PM is set and
CONFIG_PM_SLEEP is not.

This commit also deprecates the following macros:

SIMPLE_DEV_PM_OPS()
UNIVERSAL_DEV_PM_OPS()

And introduces the following macros:

DEFINE_SIMPLE_DEV_PM_OPS()
DEFINE_UNIVERSAL_DEV_PM_OPS()

These macros are similar to the functions they were created to replace,
with the following differences:

 - They use the new macros introduced above, and as such always
   reference the provided callback functions.

 - They are not tagged with __maybe_unused. They are meant to be used
   with pm_ptr() or pm_sleep_ptr() for DEFINE_UNIVERSAL_DEV_PM_OPS()
   and DEFINE_SIMPLE_DEV_PM_OPS() respectively.

 - They declare the symbol static, since every driver seems to do that
   anyway; and if a non-static use-case is needed an indirection pointer
   could be used.

The point of this change, is to progressively switch from a code model
where PM callbacks are all protected behind CONFIG_PM guards, to a code
model where the PM callbacks are always seen by the compiler, but
discarded if not used.

Signed-off-by: Paul Cercueil 
Reviewed-by: Jonathan Cameron 
Signed-off-by: Rafael J. Wysocki

PM: core: Redefine pm_ptr() macro

2021-12-17T15:04:14+00:00

The pm_ptr() macro was previously conditionally defined, according to
the value of the CONFIG_PM option. This meant that the pointed structure
was either referenced (if CONFIG_PM was set), or never referenced (if
CONFIG_PM was not set), causing it to be detected as unused by the
compiler.

This worked fine, but required the __maybe_unused compiler attribute to
be used to every symbol pointed to by a pointer wrapped with pm_ptr().

We can do better. With this change, the pm_ptr() is now defined the
same, independently of the value of CONFIG_PM. It now uses the (?:)
ternary operator to conditionally resolve to its argument. Since the
condition is known at compile time, the compiler will then choose to
discard the unused symbols, which won't need to be tagged with
__maybe_unused anymore.

This pm_ptr() macro is usually used with pointers to dev_pm_ops
structures created with SIMPLE_DEV_PM_OPS() or similar macros. These do
use a __maybe_unused flag, which is now useless with this change, so it
later can be removed. However in the meantime it causes no harm, and all
the drivers still compile fine with the new pm_ptr() macro.

Signed-off-by: Paul Cercueil 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Rafael J. Wysocki

PM: runtime: Fix unpaired parent child_count for force_resume

2021-05-10T17:14:01+00:00

As pm_runtime_need_not_resume() relies also on usage_count, it can return
a different value in pm_runtime_force_suspend() compared to when called in
pm_runtime_force_resume(). Different return values can happen if anything
calls PM runtime functions in between, and causes the parent child_count
to increase on every resume.

So far I've seen the issue only for omapdrm that does complicated things
with PM runtime calls during system suspend for legacy reasons:

omap_atomic_commit_tail() for omapdrm.0
 dispc_runtime_get()
  wakes up 58000000.dss as it's the dispc parent
   dispc_runtime_resume()
    rpm_resume() increases parent child_count
 dispc_runtime_put() won't idle, PM runtime suspend blocked
pm_runtime_force_suspend() for 58000000.dss, !pm_runtime_need_not_resume()
 __update_runtime_status()
system suspended
pm_runtime_force_resume() for 58000000.dss, pm_runtime_need_not_resume()
 pm_runtime_enable() only called because of pm_runtime_need_not_resume()
omap_atomic_commit_tail() for omapdrm.0
 dispc_runtime_get()
  wakes up 58000000.dss as it's the dispc parent
   dispc_runtime_resume()
    rpm_resume() increases parent child_count
 dispc_runtime_put() won't idle, PM runtime suspend blocked
...
rpm_suspend for 58000000.dss but parent child_count is now unbalanced

Let's fix the issue by adding a flag for needs_force_resume and use it in
pm_runtime_force_resume() instead of pm_runtime_need_not_resume().

Additionally omapdrm system suspend could be simplified later on to avoid
lots of unnecessary PM runtime calls and the complexity it adds. The
driver can just use internal functions that are shared between the PM
runtime and system suspend related functions.

Fixes: 4918e1f87c5f ("PM / runtime: Rework pm_runtime_force_suspend/resume()")
Signed-off-by: Tony Lindgren 
Reviewed-by: Ulf Hansson 
Tested-by: Tomi Valkeinen 
Cc: 4.16+  # 4.16+
Signed-off-by: Rafael J. Wysocki

PM: core: Remove duplicate declaration from header file

2021-04-07T17:18:23+00:00

struct device is declared twice, so remove the duplicate.

Signed-off-by: Wan Jiabing 
Signed-off-by: Rafael J. Wysocki