On Tuesday, June 22, 2010, Rafael J. Wysocki wrote:
> On Tuesday, June 22, 2010, Alan Stern wrote:
> > On Tue, 22 Jun 2010, Rafael J. Wysocki wrote:
...
> > > So, even if we can say when the kernel has finished processing the event
> > > (although that would be complicated in the PCIe case above), I don't think
> > > it's generally possible to ensure that the entire processing of a wakeup event
> > > has been completed. This leads to the question whether or not it is worth
> > > trying to detect the ending of the processing of a wakeup event.
> >
> > As Arve pointed out, in some cases it definitely is worthwhile (the
> > gpio keypad matrix example). In other cases there may be no reasonable
> > way to tell. That doesn't mean we have to give up entirely.
>
> Well, I'm not sure, because that really depends on the hardware and bus in
> question. The necessary condition seems to be that the event be detected
> and handled entirely by the same functional unit (eg. a device driver) within
> the kernel and such that it is able to detect whether or not user space has
> acquired the event information. That doesn't seem to be a common case to me.
Anyway, below's an update that addresses this particular case.
It adds two more functions, pm_wakeup_begin() and pm_wakeup_end()
that play similar roles to suspend_block() and suspend_unblock(), but they
don't operate on suspend blocker objects. Instead, the first of them increases
a counter of events in progress and the other one decreases this counter.
Together they have the same effect as pm_wakeup_event(), but the counter
of wakeup events in progress they operate on is also checked by
pm_check_wakeup_events().
Thus there are two ways kernel subsystems can signal wakeup events. First,
if the event is not explicitly handed over to user space and "instantaneous",
they can simply call pm_wakeup_event() and be done with it. Second, if the
event is going to be delivered to user space, the subsystem that processes
the event can call pm_wakeup_begin() right when the event is detected and
pm_wakeup_end() when it's been handed over to user space.
Please tell me what you think.
Rafael
---
drivers/base/power/Makefile | 2
drivers/base/power/main.c | 1
drivers/base/power/power.h | 3 +
drivers/base/power/sysfs.c | 9 +++
drivers/base/power/wakeup.c | 113 ++++++++++++++++++++++++++++++++++++++++
drivers/pci/pci-acpi.c | 2
drivers/pci/pcie/pme/pcie_pme.c | 2
include/linux/pm.h | 10 +++
kernel/power/hibernate.c | 14 +++-
kernel/power/main.c | 24 ++++++++
kernel/power/power.h | 7 ++
kernel/power/suspend.c | 2
12 files changed, 182 insertions(+), 7 deletions(-)
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -204,6 +204,28 @@ static ssize_t state_store(struct kobjec
power_attr(state);
+static ssize_t wakeup_count_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%lu\n", pm_get_wakeup_count());
+}
+
+static ssize_t wakeup_count_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ unsigned long val;
+
+ if (sscanf(buf, "%lu", &val) == 1) {
+ if (pm_save_wakeup_count(val))
+ return n;
+ }
+ return -EINVAL;
+}
+
+power_attr(wakeup_count);
+
#ifdef CONFIG_PM_TRACE
int pm_trace_enabled;
@@ -236,6 +258,7 @@ static struct attribute * g[] = {
#endif
#ifdef CONFIG_PM_SLEEP
&pm_async_attr.attr,
+ &wakeup_count_attr.attr,
#ifdef CONFIG_PM_DEBUG
&pm_test_attr.attr,
#endif
@@ -266,6 +289,7 @@ static int __init pm_init(void)
int error = pm_start_workqueue();
if (error)
return error;
+ pm_wakeup_events_init();
power_kobj = kobject_create_and_add("power", NULL);
if (!power_kobj)
return -ENOMEM;
Index: linux-2.6/drivers/base/power/wakeup.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/base/power/wakeup.c
@@ -0,0 +1,113 @@
+
+#include <linux/device.h>
+#include <linux/pm.h>
+
+static unsigned long event_count;
+static unsigned long saved_event_count;
+static unsigned long events_in_progress;
+static bool events_check_enabled;
+static spinlock_t events_lock;
+
+void pm_wakeup_events_init(void)
+{
+ spin_lock_init(&events_lock);
+}
+
+void pm_wakeup_event(struct device *dev)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&events_lock, flags);
+ event_count++;
+ if (dev)
+ dev->power.wakeup_count++;
+ spin_unlock_irqrestore(&events_lock, flags);
+}
+
+void pm_wakeup_begin(struct device *dev)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&events_lock, flags);
+ events_in_progress++;
+ if (dev)
+ dev->power.wakeup_count++;
+ spin_unlock_irqrestore(&events_lock, flags);
+}
+
+void pm_wakeup_end(void)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&events_lock, flags);
+ if (events_in_progress) {
+ events_in_progress--;
+ event_count++;
+ }
+ spin_unlock_irqrestore(&events_lock, flags);
+}
+
+static bool check_wakeup_events(void)
+{
+ return !events_check_enabled
+ || ((event_count == saved_event_count) && !events_in_progress);
+}
+
+bool pm_check_wakeup_events(void)
+{
+ unsigned long flags;
+ bool ret;
+
+ spin_lock_irqsave(&events_lock, flags);
+ ret = check_wakeup_events();
+ events_check_enabled = ret;
+ spin_unlock_irqrestore(&events_lock, flags);
+ return ret;
+}
+
+bool pm_check_wakeup_events_final(void)
+{
+ bool ret;
+
+ ret = check_wakeup_events();
+ events_check_enabled = false;
+ return ret;
+}
+
+unsigned long pm_get_wakeup_count(void)
+{
+ unsigned long flags;
+ unsigned long count;
+
+ spin_lock_irqsave(&events_lock, flags);
+ events_check_enabled = false;
+ count = event_count;
+ spin_unlock_irqrestore(&events_lock, flags);
+ return count;
+}
+
+bool pm_save_wakeup_count(unsigned long count)
+{
+ unsigned long flags;
+ bool ret = false;
+
+ spin_lock_irqsave(&events_lock, flags);
+ if (count == event_count) {
+ saved_event_count = count;
+ events_check_enabled = true;
+ ret = true;
+ }
+ spin_unlock_irqrestore(&events_lock, flags);
+ return ret;
+}
+
+unsigned long pm_dev_wakeup_count(struct device *dev)
+{
+ unsigned long flags;
+ unsigned long count;
+
+ spin_lock_irqsave(&events_lock, flags);
+ count = dev->power.wakeup_count;
+ spin_unlock_irqrestore(&events_lock, flags);
+ return count;
+}
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -457,6 +457,7 @@ struct dev_pm_info {
#ifdef CONFIG_PM_SLEEP
struct list_head entry;
struct completion completion;
+ unsigned long wakeup_count;
#endif
#ifdef CONFIG_PM_RUNTIME
struct timer_list suspend_timer;
@@ -552,6 +553,11 @@ extern void __suspend_report_result(cons
} while (0)
extern void device_pm_wait_for_dev(struct device *sub, struct device *dev);
+
+/* drivers/base/power/wakeup.c */
+extern void pm_wakeup_event(struct device *dev);
+extern void pm_wakeup_begin(struct device *dev);
+extern void pm_wakeup_end(void);
#else /* !CONFIG_PM_SLEEP */
#define device_pm_lock() do {} while (0)
@@ -565,6 +571,10 @@ static inline int dpm_suspend_start(pm_m
#define suspend_report_result(fn, ret) do {} while (0)
static inline void device_pm_wait_for_dev(struct device *a, struct device *b) {}
+
+static inline void pm_wakeup_event(struct device *dev) {}
+static inline void pm_wakeup_begin(struct device *dev) {}
+static inline void pm_wakeup_end(void) {}
#endif /* !CONFIG_PM_SLEEP */
/* How to reorder dpm_list after device_move() */
Index: linux-2.6/drivers/base/power/Makefile
===================================================================
--- linux-2.6.orig/drivers/base/power/Makefile
+++ linux-2.6/drivers/base/power/Makefile
@@ -1,5 +1,5 @@
obj-$(CONFIG_PM) += sysfs.o
-obj-$(CONFIG_PM_SLEEP) += main.o
+obj-$(CONFIG_PM_SLEEP) += main.o wakeup.o
obj-$(CONFIG_PM_RUNTIME) += runtime.o
obj-$(CONFIG_PM_OPS) += generic_ops.o
obj-$(CONFIG_PM_TRACE_RTC) += trace.o
Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -59,6 +59,7 @@ void device_pm_init(struct device *dev)
{
dev->power.status = DPM_ON;
init_completion(&dev->power.completion);
+ dev->power.wakeup_count = 0;
pm_runtime_init(dev);
}
Index: linux-2.6/kernel/power/power.h
===================================================================
--- linux-2.6.orig/kernel/power/power.h
+++ linux-2.6/kernel/power/power.h
@@ -184,6 +184,13 @@ static inline void suspend_test_finish(c
#ifdef CONFIG_PM_SLEEP
/* kernel/power/main.c */
extern int pm_notifier_call_chain(unsigned long val);
+
+/* drivers/base/power/wakeup.c */
+extern void pm_wakeup_events_init(void);
+extern bool pm_check_wakeup_events(void);
+extern bool pm_check_wakeup_events_final(void);
+extern unsigned long pm_get_wakeup_count(void);
+extern bool pm_save_wakeup_count(unsigned long count);
#endif
#ifdef CONFIG_HIGHMEM
Index: linux-2.6/kernel/power/suspend.c
===================================================================
--- linux-2.6.orig/kernel/power/suspend.c
+++ linux-2.6/kernel/power/suspend.c
@@ -172,7 +172,7 @@ static int suspend_enter(suspend_state_t
error = sysdev_suspend(PMSG_SUSPEND);
if (!error) {
- if (!suspend_test(TEST_CORE))
+ if (!suspend_test(TEST_CORE) && pm_check_wakeup_events_final())
error = suspend_ops->enter(state);
sysdev_resume();
}
Index: linux-2.6/kernel/power/hibernate.c
===================================================================
--- linux-2.6.orig/kernel/power/hibernate.c
+++ linux-2.6/kernel/power/hibernate.c
@@ -277,7 +277,7 @@ static int create_image(int platform_mod
goto Enable_irqs;
}
- if (hibernation_test(TEST_CORE))
+ if (hibernation_test(TEST_CORE) || !pm_check_wakeup_events())
goto Power_up;
in_suspend = 1;
@@ -511,14 +511,18 @@ int hibernation_platform_enter(void)
local_irq_disable();
sysdev_suspend(PMSG_HIBERNATE);
+ if (!pm_check_wakeup_events_final())
+ goto Power_up;
+
hibernation_ops->enter();
/* We should never get here */
while (1);
- /*
- * We don't need to reenable the nonboot CPUs or resume consoles, since
- * the system is going to be halted anyway.
- */
+ Power_up:
+ sysdev_resume();
+ local_irq_enable();
+ enable_nonboot_cpus();
+
Platform_finish:
hibernation_ops->finish();
Index: linux-2.6/drivers/pci/pci-acpi.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci-acpi.c
+++ linux-2.6/drivers/pci/pci-acpi.c
@@ -48,6 +48,8 @@ static void pci_acpi_wake_dev(acpi_handl
if (event == ACPI_NOTIFY_DEVICE_WAKE && pci_dev) {
pci_check_pme_status(pci_dev);
pm_runtime_resume(&pci_dev->dev);
+ if (device_may_wakeup(&pci_dev->dev))
+ pm_wakeup_event(&pci_dev->dev);
if (pci_dev->subordinate)
pci_pme_wakeup_bus(pci_dev->subordinate);
}
Index: linux-2.6/drivers/pci/pcie/pme/pcie_pme.c
===================================================================
--- linux-2.6.orig/drivers/pci/pcie/pme/pcie_pme.c
+++ linux-2.6/drivers/pci/pcie/pme/pcie_pme.c
@@ -154,6 +154,8 @@ static bool pcie_pme_walk_bus(struct pci
/* Skip PCIe devices in case we started from a root port. */
if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
pm_request_resume(&dev->dev);
+ if (device_may_wakeup(&dev->dev))
+ pm_wakeup_event(&dev->dev);
ret = true;
}
Index: linux-2.6/drivers/base/power/power.h
===================================================================
--- linux-2.6.orig/drivers/base/power/power.h
+++ linux-2.6/drivers/base/power/power.h
@@ -30,6 +30,9 @@ extern void device_pm_move_before(struct
extern void device_pm_move_after(struct device *, struct device *);
extern void device_pm_move_last(struct device *);
+/* drivers/base/power/wakeup.c */
+extern unsigned long pm_dev_wakeup_count(struct device *dev);
+
#else /* !CONFIG_PM_SLEEP */
static inline void device_pm_init(struct device *dev)
Index: linux-2.6/drivers/base/power/sysfs.c
===================================================================
--- linux-2.6.orig/drivers/base/power/sysfs.c
+++ linux-2.6/drivers/base/power/sysfs.c
@@ -144,6 +144,14 @@ wake_store(struct device * dev, struct d
static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
+static ssize_t wakeup_count_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%lu\n", pm_dev_wakeup_count(dev));
+}
+
+static DEVICE_ATTR(wakeup_count, 0444, wakeup_count_show, NULL);
+
#ifdef CONFIG_PM_ADVANCED_DEBUG
#ifdef CONFIG_PM_RUNTIME
@@ -230,6 +238,7 @@ static struct attribute * power_attrs[]
&dev_attr_control.attr,
#endif
&dev_attr_wakeup.attr,
+ &dev_attr_wakeup_count.attr,
#ifdef CONFIG_PM_ADVANCED_DEBUG
&dev_attr_async.attr,
#ifdef CONFIG_PM_RUNTIME
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