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PM / PCI / ACPI: Kick devices that might have been reset by firmware

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There is a concern that if the platform firmware was involved in
the system resume that's being completed,  some devices might have
been reset by it and if those devices had the power.direct_complete
flag set during the preceding suspend transition, they may stay
in a reset-power-on state indefinitely (until they are runtime-resumed
and then suspended again).  That may not be a big deal from the
individual device's perspective, but if the system is an SoC, it may
be prevented from entering deep SoC-wide low-power states on idle
because of that.

The devices that are most likely to be affected by this issue are
PCI devices and ACPI-enumerated devices using the general ACPI PM
domain, so to prevent it from happening for those devices, force a
runtime resume for them if they have their power.direct_complete
flags set and the platform firmware was involved in the resume
transition currently in progress.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki
2015-10-07 00:50:24 +02:00
parent ef25ba0476
commit 58a1fbbb2e
5 changed files with 27 additions and 20 deletions
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23
drivers/base/power/generic_ops.c
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@@ -9,6 +9,7 @@
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/export.h>
#include <linux/suspend.h>
#ifdef CONFIG_PM
/**
@@ -297,4 +298,26 @@ void pm_generic_complete(struct device *dev)
if (drv && drv->pm && drv->pm->complete)
drv->pm->complete(dev);
}
/**
* pm_complete_with_resume_check - Complete a device power transition.
* @dev: Device to handle.
*
* Complete a device power transition during a system-wide power transition and
* optionally schedule a runtime resume of the device if the system resume in
* progress has been initated by the platform firmware and the device had its
* power.direct_complete flag set.
*/
void pm_complete_with_resume_check(struct device *dev)
{
pm_generic_complete(dev);
/*
* If the device had been runtime-suspended before the system went into
* the sleep state it is going out of and it has never been resumed till
* now, resume it in case the firmware powered it up.
*/
if (dev->power.direct_complete && pm_resume_via_firmware())
pm_request_resume(dev);
}
EXPORT_SYMBOL_GPL(pm_complete_with_resume_check);
#endif /* CONFIG_PM_SLEEP */