Currently the wakeup_path status flag becomes propagated from a child
device to its parent device at __device_suspend(). This allows a driver
dealing with a parent device to act on the flag from its ->suspend()
callback.

However, in situations when the wakeup_path status flag needs to be set
from a ->suspend_late() callback, its value doesn't get propagated to the
parent by the PM core. Let's address this limitation, by also propagating
the flag at __device_suspend_late().

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

To make the code more consistent, let's clear the parent's direct_complete
flag along with clearing it for suppliers, instead of as currently, when
propagating the wakeup_path flag to parents.

While changing this, let's take the opportunity to rename the affected
internal functions, to make them self-explanatory. Like this:

dpm_clear_suppliers_direct_complete -> dpm_clear_superiors_direct_complete
dpm_propagate_to_parent -> dpm_propagate_wakeup_to_parent

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The PM core in the device_prepare() phase, resets the wakeup_path status
flag to the value of device_may_wakeup(). This means if a ->prepare() or a
->suspend() callback for the device would update the device's wakeup
setting, this doesn't become reflected in the wakeup_path status flag.

In general this isn't a problem, because wakeup settings are not supposed
to be changed (via for example calling device_set_wakeup_enable()) during
any system wide suspend/resume phase.  Nevertheless there are some users,
which can be considered as legacy, that don't conform to this behaviour.

These legacy cases should be corrected, however until that is done, let's
address the issue from the PM core, by moving the assignment of the
wakeup_path status flag to the __device_suspend() phase and after the
->suspend() callback has been invoked.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Make the PM core handle DPM_FLAG_LEAVE_SUSPENDED directly for
devices whose "noirq", "late" and "early" driver callbacks are
invoked directly by it.

Namely, make it skip all of the system-wide resume callbacks for
such devices with DPM_FLAG_LEAVE_SUSPENDED set if they are in
runtime suspend during the "noirq" phase of system-wide suspend
(or analogous) transitions or the system transition under way is
a proper suspend (rather than anything related to hibernation) and
the device's wakeup settings are compatible with runtime PM (that
is, the device cannot generate wakeup signals at all or it is
allowed to wake up the system from sleep).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Make the PM core avoid invoking the "late" and "noirq" system-wide
suspend (or analogous) callbacks provided by device drivers directly
for devices with DPM_FLAG_SMART_SUSPEND set that are in runtime
suspend during the "late" and "noirq" phases of system-wide suspend
(or analogous) transitions.  That is only done for devices without
any middle-layer "late" and "noirq" suspend callbacks (to avoid
confusing the middle layer if there is one).

The underlying observation is that runtime PM is disabled for devices
during the "late" and "noirq" system-wide suspend phases, so if they
remain in runtime suspend from the "late" phase forward, it doesn't
make sense to invoke the "late" and "noirq" callbacks provided by
the drivers for them (arguably, the device is already suspended and
in the right state).  Thus, if the remaining driver suspend callbacks
are to be invoked directly by the core, they can be skipped.

This change really makes it possible for, say, platform device
drivers to re-use runtime PM suspend and resume callbacks by
pointing ->suspend_late and ->resume_early, respectively (and
possibly the analogous hibernation-related callback pointers too),
to them without adding any extra "is the device already suspended?"
type of checks to the callback routines, as long as they will be
invoked directly by the core.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add helper routines to find and return a suitable subsystem callback
during the "noirq" phases of system suspend/resume (or analogous)
transitions as well as during the "late" phase of system suspend and
the "early" phase of system resume (or analogous) transitions.

The helpers will be called from additional sites going forward.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Make the PM core call dev_pm_skip_next_resume_phases() to skip the
"early resume" and "resume" phases of system-wide transitions to the
working state for a given device instead of clearing the relevant
status bits for it directly.

No intentional changes in functionality.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

The file was converted from print_fn_descriptor_symbol()
to %pF some time ago (c80cfb0406c01bb "vsprintf: use new
vsprintf symbolic function pointer format"). kallsyms does
not seem to be needed anymore.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Middle-layer code doing suspend-time optimizations for devices with
the DPM_FLAG_SMART_SUSPEND flag set (currently, the PCI bus type and
the ACPI PM domain) needs to make the core skip ->thaw_early and
->thaw callbacks for those devices in some cases and it sets the
power.direct_complete flag for them for this purpose.

However, it turns out that setting power.direct_complete outside of
the PM core is a bad idea as it triggers an excess invocation of
pm_runtime_enable() in device_resume().

For this reason, provide a helper to clear power.is_late_suspended
and power.is_suspended to be invoked by the middle-layer code in
question instead of setting power.direct_complete and make that code
call the new helper.

Fixes: c4b65157aeef (PCI / PM: Take SMART_SUSPEND driver flag into account)
Fixes: 05087360fd7a (ACPI / PM: Take SMART_SUSPEND driver flag into account)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>