[PATCH 4/5] ACPI PM: Replace wakeup.prepared with reference counter

Rafael J. Wysocki
2009-09-08T21:15:57Z

From: Rafael J. Wysocki <rjw@sisk.pl>

The wakeup.prepared flag is used for marking devices that have the
wake-up power already enabled, so that the wake-up power is not
enabled twice in a row for the same device. This assumes, however,
that device wake-up power will only be enabled once, while the device
is being prepared for a system-wide sleep transition, and the second
attempt is made by acpi_enable_wakeup_device_prep().

With the upcoming PCI wake-up rework this assumption will not hold
any more for PCI bridges and the root bridge whose wake-up power
may be enabled as a result of wake-up enable propagation from other
devices (eg. add-on devices that are not associated with any GPEs).
Thus, there may be many attempts to enable wake-up power on a PCI
bridge or the root bridge during a system power state transition
and it's better to replace wakeup.prepared with a reference counter.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/acpi/power.c | 58 ++++++++++++++++++++++++++++--------------------
drivers/acpi/scan.c | 1
drivers/acpi/wakeup.c | 4 +--
include/acpi/acpi_bus.h | 2 -
4 files changed, 39 insertions(+), 26 deletions(-)

Index: linux-2.6/drivers/acpi/scan.c
===================================================================
--- linux-2.6.orig/drivers/acpi/scan.c
+++ linux-2.6/drivers/acpi/scan.c
@@ -781,6 +781,7 @@ static int acpi_bus_get_wakeup_device_fl
kfree(buffer.pointer);

device->wakeup.flags.valid = 1;
+ device->wakeup.prepare_count = 0;
/* Call _PSW/_DSW object to disable its ability to wake the sleeping
* system for the ACPI device with the _PRW object.
* The _PSW object is depreciated in ACPI 3.0 and is replaced by _DSW.
Index: linux-2.6/include/acpi/acpi_bus.h
===================================================================
--- linux-2.6.orig/include/acpi/acpi_bus.h
+++ linux-2.6/include/acpi/acpi_bus.h
@@ -248,7 +248,6 @@ struct acpi_device_perf {
/* Wakeup Management */
struct acpi_device_wakeup_flags {
u8 valid:1; /* Can successfully enable wakeup? */
- u8 prepared:1; /* Has the wake-up capability been enabled? */
u8 run_wake:1; /* Run-Wake GPE devices */
};

@@ -263,6 +262,7 @@ struct acpi_device_wakeup {
struct acpi_handle_list resources;
struct acpi_device_wakeup_state state;
struct acpi_device_wakeup_flags flags;
+ int prepare_count;
};

/* Device */
Index: linux-2.6/drivers/acpi/power.c
===================================================================
--- linux-2.6.orig/drivers/acpi/power.c
+++ linux-2.6/drivers/acpi/power.c
@@ -44,6 +44,8 @@
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>

+#include "sleep.h"
+
#define _COMPONENT ACPI_POWER_COMPONENT
ACPI_MODULE_NAME("power");
#define ACPI_POWER_CLASS "power_resource"
@@ -361,17 +363,15 @@ int acpi_device_sleep_wake(struct acpi_d
*/
int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
{
- int i, err;
+ int i, err = 0;

if (!dev || !dev->wakeup.flags.valid)
return -EINVAL;

- /*
- * Do not execute the code below twice in a row without calling
- * acpi_disable_wakeup_device_power() in between for the same device
- */
- if (dev->wakeup.flags.prepared)
- return 0;
+ mutex_lock(&acpi_device_lock);
+
+ if (dev->wakeup.prepare_count++)
+ goto out;

/* Open power resource */
for (i = 0; i < dev->wakeup.resources.count; i++) {
@@ -379,7 +379,8 @@ int acpi_enable_wakeup_device_power(stru
if (ret) {
printk(KERN_ERR PREFIX "Transition power state\n");
dev->wakeup.flags.valid = 0;
- return -ENODEV;
+ err = -ENODEV;
+ goto err_out;
}
}

@@ -388,9 +389,13 @@ int acpi_enable_wakeup_device_power(stru
* in arbitrary power state afterwards.
*/
err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
- if (!err)
- dev->wakeup.flags.prepared = 1;

+ err_out:
+ if (err)
+ dev->wakeup.prepare_count = 0;
+
+ out:
+ mutex_unlock(&acpi_device_lock);
return err;
}

@@ -402,35 +407,42 @@ int acpi_enable_wakeup_device_power(stru
*/
int acpi_disable_wakeup_device_power(struct acpi_device *dev)
{
- int i, ret;
+ int i, err = 0;

if (!dev || !dev->wakeup.flags.valid)
return -EINVAL;

+ mutex_lock(&acpi_device_lock);
+
+ if (--dev->wakeup.prepare_count > 0)
+ goto out;
+
/*
- * Do not execute the code below twice in a row without calling
- * acpi_enable_wakeup_device_power() in between for the same device
+ * Executing the code below even if prepare_count is already zero when
+ * the function is called may be useful, for example for initialisation.
*/
- if (!dev->wakeup.flags.prepared)
- return 0;
+ if (dev->wakeup.prepare_count < 0)
+ dev->wakeup.prepare_count = 0;

- dev->wakeup.flags.prepared = 0;
-
- ret = acpi_device_sleep_wake(dev, 0, 0, 0);
- if (ret)
- return ret;
+ err = acpi_device_sleep_wake(dev, 0, 0, 0);
+ if (err)
+ goto out;

/* Close power resource */
for (i = 0; i < dev->wakeup.resources.count; i++) {
- ret = acpi_power_off_device(dev->wakeup.resources.handles[i], dev);
+ int ret = acpi_power_off_device(
+ dev->wakeup.resources.handles[i], dev);
if (ret) {
printk(KERN_ERR PREFIX "Transition power state\n");
dev->wakeup.flags.valid = 0;
- return -ENODEV;
+ err = -ENODEV;
+ goto out;
}
}

- return ret;
+ out:
+ mutex_unlock(&acpi_device_lock);
+ return err;
}

/* --------------------------------------------------------------------------
Index: linux-2.6/drivers/acpi/wakeup.c
===================================================================
--- linux-2.6.orig/drivers/acpi/wakeup.c
+++ linux-2.6/drivers/acpi/wakeup.c
@@ -68,7 +68,7 @@ void acpi_enable_wakeup_device(u8 sleep_
/* If users want to disable run-wake GPE,
* we only disable it for wake and leave it for runtime
*/
- if ((!dev->wakeup.state.enabled && !dev->wakeup.flags.prepared)
+ if ((!dev->wakeup.state.enabled && !dev->wakeup.prepare_count)
|| sleep_state > (u32) dev->wakeup.sleep_state) {
if (dev->wakeup.flags.run_wake) {
/* set_gpe_type will disable GPE, leave it like that */
@@ -100,7 +100,7 @@ void acpi_disable_wakeup_device(u8 sleep
if (!dev->wakeup.flags.valid)
continue;

- if ((!dev->wakeup.state.enabled && !dev->wakeup.flags.prepared)
+ if ((!dev->wakeup.state.enabled && !dev->wakeup.prepare_count)
|| sleep_state > (u32) dev->wakeup.sleep_state) {
if (dev->wakeup.flags.run_wake) {
acpi_set_gpe_type(dev->wakeup.gpe_device,