[RFC][PATCH 4/4] PCI/ACPI PM: Propagate wake-up enable for devices w/o ACPI support

Rafael J. Wysocki
2009-09-03T22:07:09Z

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

Some PCI devices (not PCI Express), like PCI add-on cards, can
generate PME#, but they don't have any special platform wake-up
support. For this reason, even if they generate PME# to wake up the
system from a sleep state, wake-up events are not generated by the
platform.

It turns out that, at least on some systems, PCI bridges and the PCI
host bridge have ACPI GPEs associated with them that, if enabled to
generate wake-up events, allow the system to wake up if one of the
add-on devices asserts PME# while the system is in a sleep state.
Following this observation, if a PCI device without direct ACPI
wake-up support is prepared to wake up the system during a transition
into a sleep state (eg. suspend to RAM), configure all the bridges on
the path from the device to the root bridge (including the root
bridge itself) to wake-up the system.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/acpi/power.c | 52 ++++++++++++++++++++++++++++++++----------------
drivers/acpi/scan.c | 1
drivers/acpi/sleep.c | 2 -
drivers/acpi/wakeup.c | 4 +--
drivers/pci/pci-acpi.c | 25 +++++++++++++++++++++--
include/acpi/acpi_bus.h | 2 -
6 files changed, 63 insertions(+), 23 deletions(-)

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
@@ -109,10 +109,31 @@ static bool acpi_pci_can_wakeup(struct p
return handle ? acpi_bus_can_wakeup(handle) : false;
}

+static void acpi_pci_propagate_wakeup_enable(struct pci_bus *bus, bool enable)
+{
+ while (bus->parent) {
+ struct pci_dev *bridge = bus->self;
+
+ acpi_pm_device_sleep_wake(&bridge->dev, enable);
+ if (bridge->is_pcie)
+ return;
+ bus = bus->parent;
+ }
+
+ /* We have reached the root bus. */
+ if (bus->bridge)
+ acpi_pm_device_sleep_wake(bus->bridge, enable);
+}
+
static int acpi_pci_sleep_wake(struct pci_dev *dev, bool enable)
{
- return acpi_pci_can_wakeup(dev) ?
- acpi_pm_device_sleep_wake(&dev->dev, enable) : 0;
+ if (acpi_pci_can_wakeup(dev))
+ return acpi_pm_device_sleep_wake(&dev->dev, enable);
+
+ if (!dev->is_pcie)
+ acpi_pci_propagate_wakeup_enable(dev->bus, enable);
+
+ return 0;
}

static struct pci_platform_pm_ops acpi_pci_platform_pm = {
Index: linux-2.6/drivers/acpi/sleep.c
===================================================================
--- linux-2.6.orig/drivers/acpi/sleep.c
+++ linux-2.6/drivers/acpi/sleep.c
@@ -691,7 +691,7 @@ int acpi_pm_device_sleep_wake(struct dev
struct acpi_device *adev;
int error;

- if (!device_may_wakeup(dev))
+ if (!device_can_wakeup(dev))
return -EINVAL;

handle = DEVICE_ACPI_HANDLE(dev);
Index: linux-2.6/drivers/acpi/scan.c
===================================================================
--- linux-2.6.orig/drivers/acpi/scan.c
+++ linux-2.6/drivers/acpi/scan.c
@@ -782,6 +782,7 @@ 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 +363,19 @@ 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;

+ mutex_lock(&acpi_device_lock);
+
/*
* 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;
+ if (dev->wakeup.prepare_count++)
+ goto out;

/* Open power resource */
for (i = 0; i < dev->wakeup.resources.count; i++) {
@@ -379,7 +383,8 @@ 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 +393,13 @@ 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 +411,44 @@ 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);
+
/*
* Do not execute the code below twice in a row without calling
* acpi_enable_wakeup_device_power() in between for the same device
*/
- if (!dev->wakeup.flags.prepared)
- return 0;
-
- dev->wakeup.flags.prepared = 0;
+ if (--dev->wakeup.prepare_count) {
+ if (dev->wakeup.prepare_count < 0) {
+ dev_warn(&dev->dev, "unbalanced %s!\n", __func__);
+ dev->wakeup.prepare_count = 0;
+ }
+ goto out;
+ }

- 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,