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PM: domains: Don't runtime resume devices at genpd_prepare()

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Runtime resuming a device upfront in the genpd_prepare() callback,
to check if there is a wakeup pending for it, seems like an
unnecessary thing to do.

The PM core already manages these kind of things in a common way in
__device_suspend(), via calling pm_runtime_barrier() and
pm_wakeup_pending().

Therefore, let's simply drop this behaviour from genpd_prepare().

Note that, this change is applicable only for devices that are
attached to a genpd that has the GENPD_FLAG_ACTIVE_WAKEUP set
(Renesas, Mediatek, and Rockchip platforms). Moreover, a driver
that needs to restore power for its device to re-configure it
for a system wakeup, may still call pm_runtime_get_sync(), for
example, to do this.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Ulf Hansson 2021-03-04 20:28:43 +01:00 committed by Rafael J. Wysocki
parent 1e28eed176
commit c1df456d0f
1 changed files with 0 additions and 36 deletions
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36
drivers/base/power/domain.c
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@ -1087,34 +1087,6 @@ static void genpd_sync_power_on(struct generic_pm_domain *genpd, bool use_lock,
genpd->status = GENPD_STATE_ON;
}
/**
* resume_needed - Check whether to resume a device before system suspend.
* @dev: Device to check.
* @genpd: PM domain the device belongs to.
*
* There are two cases in which a device that can wake up the system from sleep
* states should be resumed by genpd_prepare(): (1) if the device is enabled
* to wake up the system and it has to remain active for this purpose while the
* system is in the sleep state and (2) if the device is not enabled to wake up
* the system from sleep states and it generally doesn't generate wakeup signals
* by itself (those signals are generated on its behalf by other parts of the
* system). In the latter case it may be necessary to reconfigure the device's
* wakeup settings during system suspend, because it may have been set up to
* signal remote wakeup from the system's working state as needed by runtime PM.
* Return 'true' in either of the above cases.
*/
static bool resume_needed(struct device *dev,
const struct generic_pm_domain *genpd)
{
bool active_wakeup;
if (!device_can_wakeup(dev))
return false;
active_wakeup = genpd_is_active_wakeup(genpd);
return device_may_wakeup(dev) ? active_wakeup : !active_wakeup;
}
/**
* genpd_prepare - Start power transition of a device in a PM domain.
* @dev: Device to start the transition of.
@ -1135,14 +1107,6 @@ static int genpd_prepare(struct device *dev)
if (IS_ERR(genpd))
return -EINVAL;
/*
* If a wakeup request is pending for the device, it should be woken up
* at this point and a system wakeup event should be reported if it's
* set up to wake up the system from sleep states.
*/
if (resume_needed(dev, genpd))
pm_runtime_resume(dev);
genpd_lock(genpd);
if (genpd->prepared_count++ == 0)