lkml.org 
[lkml]   [2017]   [Oct]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 06/12] PCI / PM: Take SMART_SUSPEND driver flag into account
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.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@intel.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

\
 
 \ /
  Last update: 2017-10-16 03:47    [W:0.345 / U:7.820 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site