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PM / QoS: Make it possible to expose PM QoS device flags to user space

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Define two device PM QoS flags, PM_QOS_FLAG_NO_POWER_OFF
and PM_QOS_FLAG_REMOTE_WAKEUP, and introduce routines
dev_pm_qos_expose_flags() and dev_pm_qos_hide_flags() allowing the
caller to expose those two flags to user space or to hide them
from it, respectively.

After the flags have been exposed, user space will see two
additional sysfs attributes, pm_qos_no_power_off and
pm_qos_remote_wakeup, under the device's /sys/devices/.../power/
directory.  Then, writing 1 to one of them will update the
PM QoS flags request owned by user space so that the corresponding
flag is requested to be set.  In turn, writing 0 to one of them
will cause the corresponding flag in the user space's request to
be cleared (however, the owners of the other PM QoS flags requests
for the same device may still request the flag to be set and it
may be effectively set even if user space doesn't request that).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Jean Pihet <j-pihet@ti.com>
Acked-by: mark gross <markgross@thegnar.org>
This commit is contained in:
Rafael J. Wysocki
2012-10-24 02:08:18 +02:00
parent ae0fb4b72c
commit e39473d0b9
6 changed files with 278 additions and 48 deletions
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31
Documentation/ABI/testing/sysfs-devices-power
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@@ -204,3 +204,34 @@ Description:
This attribute has no effect on system-wide suspend/resume and
hibernation.
What: /sys/devices/.../power/pm_qos_no_power_off
Date: September 2012
Contact: Rafael J. Wysocki <rjw@sisk.pl>
Description:
The /sys/devices/.../power/pm_qos_no_power_off attribute
is used for manipulating the PM QoS "no power off" flag. If
set, this flag indicates to the kernel that power should not
be removed entirely from the device.
Not all drivers support this attribute. If it isn't supported,
it is not present.
This attribute has no effect on system-wide suspend/resume and
hibernation.
What: /sys/devices/.../power/pm_qos_remote_wakeup
Date: September 2012
Contact: Rafael J. Wysocki <rjw@sisk.pl>
Description:
The /sys/devices/.../power/pm_qos_remote_wakeup attribute
is used for manipulating the PM QoS "remote wakeup required"
flag. If set, this flag indicates to the kernel that the
device is a source of user events that have to be signaled from
its low-power states.
Not all drivers support this attribute. If it isn't supported,
it is not present.
This attribute has no effect on system-wide suspend/resume and
hibernation.