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authorRafael J. Wysocki <rjw@sisk.pl>2010-01-23 16:25:23 -0500
committerRafael J. Wysocki <rjw@sisk.pl>2010-02-26 14:39:10 -0500
commit5a2eb8585f3b38e01e30aacaa8b985a1520a993d (patch)
tree471b33cc48cf48ed491e8b3f2934bfb3fa9e81e1 /Documentation/ABI/testing/sysfs-devices-power
parent0e06b4a891c6a108412fe24b4500f499da2cf8a1 (diff)
PM: Add facility for advanced testing of async suspend/resume
Add configuration switch CONFIG_PM_ADVANCED_DEBUG for compiling in extra PM debugging/testing code allowing one to access some PM-related attributes of devices from the user space via sysfs. If CONFIG_PM_ADVANCED_DEBUG is set, add sysfs attribute power/async for every device allowing the user space to access the device's power.async_suspend flag and modify it, if desired. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-devices-power')
-rw-r--r--Documentation/ABI/testing/sysfs-devices-power26
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power
index 431bfd7e65c7..6123c523bfd7 100644
--- a/Documentation/ABI/testing/sysfs-devices-power
+++ b/Documentation/ABI/testing/sysfs-devices-power
@@ -51,3 +51,29 @@ Description:
51 drivers. Changing this attribute to "on" prevents the driver 51 drivers. Changing this attribute to "on" prevents the driver
52 from power managing the device at run time. Doing that while 52 from power managing the device at run time. Doing that while
53 the device is suspended causes it to be woken up. 53 the device is suspended causes it to be woken up.
54
55What: /sys/devices/.../power/async
56Date: January 2009
57Contact: Rafael J. Wysocki <rjw@sisk.pl>
58Description:
59 The /sys/devices/.../async attribute allows the user space to
60 enable or diasble the device's suspend and resume callbacks to
61 be executed asynchronously (ie. in separate threads, in parallel
62 with the main suspend/resume thread) during system-wide power
63 transitions (eg. suspend to RAM, hibernation).
64
65 All devices have one of the following two values for the
66 power/async file:
67
68 + "enabled\n" to permit the asynchronous suspend/resume;
69 + "disabled\n" to forbid it;
70
71 The value of this attribute may be changed by writing either
72 "enabled", or "disabled" to it.
73
74 It generally is unsafe to permit the asynchronous suspend/resume
75 of a device unless it is certain that all of the PM dependencies
76 of the device are known to the PM core. However, for some
77 devices this attribute is set to "enabled" by bus type code or
78 device drivers and in that cases it should be safe to leave the
79 default value.