From: Rafael J. Wysocki <rjw@xxxxxxx>
It turns out that some PCI devices are only found to be
wakeup-capable during registration, in which case, when
device_set_wakeup_capable() is called, device_is_registered() already
returns 'true' for the given device, but dpm_sysfs_add() hasn't been
called for it yet. This leads to situations in which the device's
power.can_wakeup flag is not set as requested because of failing
wakeup_sysfs_add() and its wakeup-related sysfs files are not
created, although they should be present. This is a post-2.6.38
regression introduced by commit cb8f51bdadb7969139c2e39c2defd4cde98c1
(PM: Do not create wakeup sysfs files for devices that cannot wake
up).
To work around this problem initialize the device's power.entry
field to an empty list head and make device_set_wakeup_capable()
check if it is still empty before attempting to add the devices
wakeup-related sysfs files with wakeup_sysfs_add(). Namely, if
power.entry is still empty at this point, device_pm_add() hasn't been
called yet for the device and its wakeup-related files will be
created later, so device_set_wakeup_capable() doesn't have to create
them.
Reported-by: Tino Keitel <tino.keitel@xxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
drivers/base/power/main.c | 1 +
drivers/base/power/wakeup.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
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
@@ -63,6 +63,7 @@ void device_pm_init(struct device *dev)
dev->power.wakeup = NULL;
spin_lock_init(&dev->power.lock);
pm_runtime_init(dev);
+ INIT_LIST_HEAD(&dev->power.entry);
}
/**
Index: linux-2.6/drivers/base/power/wakeup.c
===================================================================
--- linux-2.6.orig/drivers/base/power/wakeup.c
+++ linux-2.6/drivers/base/power/wakeup.c
@@ -258,7 +258,7 @@ void device_set_wakeup_capable(struct de
if (!!dev->power.can_wakeup == !!capable)
return;
- if (device_is_registered(dev)) {
+ if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
if (capable) {
if (wakeup_sysfs_add(dev))
return;
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