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Message-ID: <12906785.qsTjxC3pk6@aspire.rjw.lan>
Date: Mon, 16 Oct 2017 03:29:47 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
Alan Stern <stern@...land.harvard.edu>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
LKML <linux-kernel@...r.kernel.org>,
Linux ACPI <linux-acpi@...r.kernel.org>,
Linux PCI <linux-pci@...r.kernel.org>,
Linux Documentation <linux-doc@...r.kernel.org>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
Ulf Hansson <ulf.hansson@...aro.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Kevin Hilman <khilman@...nel.org>,
Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 06/12] PCI / PM: Take SMART_SUSPEND driver flag into account
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Make the PCI bus type take DPM_FLAG_SMART_SUSPEND into account in its
system suspend callbacks and make sure that all code that should not
run in parallel with pci_pm_runtime_resume() is executed in the "late"
phases of system suspend, freeze and poweroff transitions.
[Note that the pm_runtime_suspended() check in pci_dev_keep_suspended()
is an optimization, because if is not passed, all of the subsequent
checks may be skipped and some of them are much more overhead in
general.]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
---
Documentation/power/pci.txt | 6 ++++
drivers/pci/pci-driver.c | 56 ++++++++++++++++++++++++++++++--------------
2 files changed, 45 insertions(+), 17 deletions(-)
Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -727,18 +727,25 @@ static int pci_pm_suspend(struct device
if (!pm) {
pci_pm_default_suspend(pci_dev);
- goto Fixup;
+ return 0;
}
/*
- * PCI devices suspended at run time need to be resumed at this point,
- * because in general it is necessary to reconfigure them for system
- * suspend. Namely, if the device is supposed to wake up the system
- * from the sleep state, we may need to reconfigure it for this purpose.
- * In turn, if the device is not supposed to wake up the system from the
- * sleep state, we'll have to prevent it from signaling wake-up.
+ * PCI devices suspended at run time may need to be resumed at this
+ * point, because in general it may be necessary to reconfigure them for
+ * system suspend. Namely, if the device is expected to wake up the
+ * system from the sleep state, it may have to be reconfigured for this
+ * purpose, or if the device is not expected to wake up the system from
+ * the sleep state, it should be prevented from signaling wakeup events
+ * going forward.
+ *
+ * Also if the driver of the device does not indicate that its system
+ * suspend callbacks can cope with runtime-suspended devices, it is
+ * better to resume the device from runtime suspend here.
*/
- pm_runtime_resume(dev);
+ if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
+ !pci_dev_keep_suspended(pci_dev))
+ pm_runtime_resume(dev);
pci_dev->state_saved = false;
if (pm->suspend) {
@@ -758,12 +765,16 @@ static int pci_pm_suspend(struct device
}
}
- Fixup:
- pci_fixup_device(pci_fixup_suspend, pci_dev);
-
return 0;
}
+static int pci_pm_suspend_late(struct device *dev)
+{
+ pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev));
+
+ return pm_generic_suspend_late(dev);;
+}
+
static int pci_pm_suspend_noirq(struct device *dev)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
@@ -872,6 +883,7 @@ static int pci_pm_resume(struct device *
#else /* !CONFIG_SUSPEND */
#define pci_pm_suspend NULL
+#define pci_pm_suspend_late NULL
#define pci_pm_suspend_noirq NULL
#define pci_pm_resume NULL
#define pci_pm_resume_noirq NULL
@@ -906,7 +918,8 @@ static int pci_pm_freeze(struct device *
* devices should not be touched during freeze/thaw transitions,
* however.
*/
- pm_runtime_resume(dev);
+ if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND))
+ pm_runtime_resume(dev);
pci_dev->state_saved = false;
if (pm->freeze) {
@@ -1004,11 +1017,13 @@ static int pci_pm_poweroff(struct device
if (!pm) {
pci_pm_default_suspend(pci_dev);
- goto Fixup;
+ return 0;
}
/* The reason to do that is the same as in pci_pm_suspend(). */
- pm_runtime_resume(dev);
+ if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
+ !pci_dev_keep_suspended(pci_dev))
+ pm_runtime_resume(dev);
pci_dev->state_saved = false;
if (pm->poweroff) {
@@ -1020,12 +1035,16 @@ static int pci_pm_poweroff(struct device
return error;
}
- Fixup:
- pci_fixup_device(pci_fixup_suspend, pci_dev);
-
return 0;
}
+static int pci_pm_poweroff_late(struct device *dev)
+{
+ pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev));
+
+ return pm_generic_poweroff_late(dev);
+}
+
static int pci_pm_poweroff_noirq(struct device *dev)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
@@ -1124,6 +1143,7 @@ static int pci_pm_restore(struct device
#define pci_pm_thaw NULL
#define pci_pm_thaw_noirq NULL
#define pci_pm_poweroff NULL
+#define pci_pm_poweroff_late NULL
#define pci_pm_poweroff_noirq NULL
#define pci_pm_restore NULL
#define pci_pm_restore_noirq NULL
@@ -1239,10 +1259,12 @@ static const struct dev_pm_ops pci_dev_p
.prepare = pci_pm_prepare,
.complete = pci_pm_complete,
.suspend = pci_pm_suspend,
+ .suspend_late = pci_pm_suspend_late,
.resume = pci_pm_resume,
.freeze = pci_pm_freeze,
.thaw = pci_pm_thaw,
.poweroff = pci_pm_poweroff,
+ .poweroff_late = pci_pm_poweroff_late,
.restore = pci_pm_restore,
.suspend_noirq = pci_pm_suspend_noirq,
.resume_noirq = pci_pm_resume_noirq,
Index: linux-pm/Documentation/power/pci.txt
===================================================================
--- linux-pm.orig/Documentation/power/pci.txt
+++ linux-pm/Documentation/power/pci.txt
@@ -980,6 +980,12 @@ positive value from pci_pm_prepare() if
driver of the device returns a positive value. That allows the driver to opt
out from using the direct-complete mechanism dynamically.
+The DPM_FLAG_SMART_SUSPEND flag tells the PCI bus type that from the driver's
+perspective the device can be safely left in runtime suspend during system
+suspend. That causes pci_pm_suspend(), pci_pm_freeze() and pci_pm_poweroff()
+to skip resuming the device from runtime suspend unless there are PCI-specific
+reasons for doing that.
+
3.2. Device Runtime Power Management
------------------------------------
In addition to providing device power management callbacks PCI device drivers
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