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Message-ID: <2845319.uTdi8Ml1JD@vostro.rjw.lan>
Date: Fri, 02 Oct 2015 03:54:52 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM list <linux-pm@...r.kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Alan Stern <stern@...land.harvard.edu>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Daniel Vetter <daniel.vetter@...el.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Linux PCI <linux-pci@...r.kernel.org>
Subject: [RFC][PATCH v2 2/2] PM / PCI / ACPI: Kick devices that might have been reset by firmware
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
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@...el.com>
---
v1 -> v2: Do it for devices that are most likely to be affected (PCI and the
ACPI PM domain users) rather than for all devices in the system.
---
drivers/acpi/acpi_lpss.c | 2 +-
drivers/acpi/device_pm.c | 19 +------------------
drivers/base/power/generic_ops.c | 23 +++++++++++++++++++++++
drivers/pci/pci-driver.c | 2 +-
include/linux/pm.h | 2 +-
5 files changed, 27 insertions(+), 21 deletions(-)
Index: linux-pm/drivers/acpi/device_pm.c
===================================================================
--- linux-pm.orig/drivers/acpi/device_pm.c
+++ linux-pm/drivers/acpi/device_pm.c
@@ -963,23 +963,6 @@ int acpi_subsys_prepare(struct device *d
EXPORT_SYMBOL_GPL(acpi_subsys_prepare);
/**
- * acpi_subsys_complete - Finalize device's resume during system resume.
- * @dev: Device to handle.
- */
-void acpi_subsys_complete(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_request_resume(dev);
-}
-EXPORT_SYMBOL_GPL(acpi_subsys_complete);
-
-/**
* acpi_subsys_suspend - Run the device driver's suspend callback.
* @dev: Device to handle.
*
@@ -1047,7 +1030,7 @@ static struct dev_pm_domain acpi_general
.runtime_resume = acpi_subsys_runtime_resume,
#ifdef CONFIG_PM_SLEEP
.prepare = acpi_subsys_prepare,
- .complete = acpi_subsys_complete,
+ .complete = pm_complete_with_resume_check,
.suspend = acpi_subsys_suspend,
.suspend_late = acpi_subsys_suspend_late,
.resume_early = acpi_subsys_resume_early,
Index: linux-pm/drivers/acpi/acpi_lpss.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpi_lpss.c
+++ linux-pm/drivers/acpi/acpi_lpss.c
@@ -664,7 +664,7 @@ static struct dev_pm_domain acpi_lpss_pm
#ifdef CONFIG_PM
#ifdef CONFIG_PM_SLEEP
.prepare = acpi_subsys_prepare,
- .complete = acpi_subsys_complete,
+ .complete = pm_complete_with_resume_check,
.suspend = acpi_subsys_suspend,
.suspend_late = acpi_lpss_suspend_late,
.resume_early = acpi_lpss_resume_early,
Index: linux-pm/drivers/base/power/generic_ops.c
===================================================================
--- linux-pm.orig/drivers/base/power/generic_ops.c
+++ linux-pm/drivers/base/power/generic_ops.c
@@ -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 *
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 */
Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -687,7 +687,7 @@ static int pci_pm_prepare(struct device
static void pci_pm_complete(struct device *dev)
{
pci_dev_complete_resume(to_pci_dev(dev));
- pm_generic_complete(dev);
+ pm_complete_with_resume_check(dev);
}
#else /* !CONFIG_PM_SLEEP */
Index: linux-pm/include/linux/pm.h
===================================================================
--- linux-pm.orig/include/linux/pm.h
+++ linux-pm/include/linux/pm.h
@@ -731,7 +731,7 @@ extern int pm_generic_restore(struct dev
extern int pm_generic_poweroff_noirq(struct device *dev);
extern int pm_generic_poweroff_late(struct device *dev);
extern int pm_generic_poweroff(struct device *dev);
-extern void pm_generic_complete(struct device *dev);
+extern void pm_complete_with_resume_check(struct device *dev);
#else /* !CONFIG_PM_SLEEP */
--
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