When using runtime PM in combination with CPUidle, the runtime PM
transtions of some devices may be triggered during the idle path.
Late in the idle sequence, interrupts will likely be disabled when
runtime PM for these devices is initiated.
Currently, the runtime PM core assumes methods are called with
interrupts enabled. However, if it is called with interrupts
disabled, the internal locking unconditionally enables interrupts, for
example:
pm_runtime_put_sync()
__pm_runtime_put()
pm_runtime_idle()
spin_lock_irq()
__pm_runtime_idle()
spin_unlock_irq() <--- interrupts unconditionally enabled
dev->bus->pm->runtime_idle()
spin_lock_irq()
spin_unlock_irq()
Unconditionally enabling interrupts late in the idle sequence is not
desired behavior. To fix, use the save/restore versions of the
spinlock API.
Reported-by: Partha Basak <p-bas...@ti.com>
Signed-off-by: Kevin Hilman <khil...@deeprootsystems.com>
---
RFC: I'm not crazy about having the 'flags' in struct dev_pm_info, but
since the locks are taken and released in separate functions, this
seems better than changing the function APIs to pass around the flags.
drivers/base/power/runtime.c | 68 ++++++++++++++++++++++-------------------
include/linux/pm.h | 1 +
2 files changed, 37 insertions(+), 32 deletions(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index b78c401..0caaef1 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -80,24 +80,24 @@ static int __pm_runtime_idle(struct device *dev)
dev->power.idle_notification = true;
if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_idle) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
dev->bus->pm->runtime_idle(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
} else if (dev->type && dev->type->pm && dev->type->pm->runtime_idle) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
dev->type->pm->runtime_idle(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
} else if (dev->class && dev->class->pm
&& dev->class->pm->runtime_idle) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
dev->class->pm->runtime_idle(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
}
dev->power.idle_notification = false;
@@ -115,9 +115,9 @@ int pm_runtime_idle(struct device *dev)
{
int retval;
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
retval = __pm_runtime_idle(dev);
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
return retval;
}
@@ -226,11 +226,13 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
if (dev->power.runtime_status != RPM_SUSPENDING)
break;
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock,
+ dev->power.lock_flags);
schedule();
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock,
+ dev->power.lock_flags);
}
finish_wait(&dev->power.wait_queue, &wait);
goto repeat;
@@ -240,27 +242,27 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
dev->power.deferred_resume = false;
if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
retval = dev->bus->pm->runtime_suspend(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
dev->power.runtime_error = retval;
} else if (dev->type && dev->type->pm
&& dev->type->pm->runtime_suspend) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
retval = dev->type->pm->runtime_suspend(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
dev->power.runtime_error = retval;
} else if (dev->class && dev->class->pm
&& dev->class->pm->runtime_suspend) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
retval = dev->class->pm->runtime_suspend(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
dev->power.runtime_error = retval;
} else {
retval = -ENOSYS;
@@ -296,11 +298,11 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
__pm_runtime_idle(dev);
if (parent && !parent->power.ignore_children) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
pm_request_idle(parent);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
}
out:
@@ -317,9 +319,9 @@ int pm_runtime_suspend(struct device *dev)
{
int retval;
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
retval = __pm_runtime_suspend(dev, false);
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
return retval;
}
@@ -381,11 +383,13 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
&& dev->power.runtime_status != RPM_SUSPENDING)
break;
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock,
+ dev->power.lock_flags);
schedule();
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock,
+ dev->power.lock_flags);
}
finish_wait(&dev->power.wait_queue, &wait);
goto repeat;
@@ -423,27 +427,27 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
__update_runtime_status(dev, RPM_RESUMING);
if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
retval = dev->bus->pm->runtime_resume(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
dev->power.runtime_error = retval;
} else if (dev->type && dev->type->pm
&& dev->type->pm->runtime_resume) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
retval = dev->type->pm->runtime_resume(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
dev->power.runtime_error = retval;
} else if (dev->class && dev->class->pm
&& dev->class->pm->runtime_resume) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
retval = dev->class->pm->runtime_resume(dev);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
dev->power.runtime_error = retval;
} else {
retval = -ENOSYS;
@@ -464,11 +468,11 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
out:
if (parent) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
pm_runtime_put(parent);
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
}
dev_dbg(dev, "__pm_runtime_resume() returns %d!\n", retval);
@@ -484,9 +488,9 @@ int pm_runtime_resume(struct device *dev)
{
int retval;
- spin_lock_irq(&dev->power.lock);
+ spin_lock_irqsave(&dev->power.lock, dev->power.lock_flags);
retval = __pm_runtime_resume(dev, false);
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock_irqrestore(&dev->power.lock, dev->power.lock_flags);
return retval;
}
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 52e8c55..8515153 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -465,6 +465,7 @@ struct dev_pm_info {
struct work_struct work;
wait_queue_head_t wait_queue;
spinlock_t lock;
+ unsigned long lock_flags;
atomic_t usage_count;
atomic_t child_count;
unsigned int disable_depth:3;
--
1.7.2.1
--
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