diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-power | 20 | ||||
| -rw-r--r-- | Documentation/power/devices.txt | 20 |
2 files changed, 20 insertions, 20 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 7628cd1bc36a..8ffbc25376a0 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -29,9 +29,8 @@ Description: "disabled" to it. For the devices that are not capable of generating system wakeup - events this file contains "\n". In that cases the user space - cannot modify the contents of this file and the device cannot be - enabled to wake up the system. + events this file is not present. In that case the device cannot + be enabled to wake up the system from sleep states. What: /sys/devices/.../power/control Date: January 2009 @@ -85,7 +84,7 @@ Description: The /sys/devices/.../wakeup_count attribute contains the number of signaled wakeup events associated with the device. This attribute is read-only. If the device is not enabled to wake up - the system from sleep states, this attribute is empty. + the system from sleep states, this attribute is not present. What: /sys/devices/.../power/wakeup_active_count Date: September 2010 @@ -95,7 +94,7 @@ Description: number of times the processing of wakeup events associated with the device was completed (at the kernel level). This attribute is read-only. If the device is not enabled to wake up the - system from sleep states, this attribute is empty. + system from sleep states, this attribute is not present. What: /sys/devices/.../power/wakeup_hit_count Date: September 2010 @@ -105,7 +104,8 @@ Description: number of times the processing of a wakeup event associated with the device might prevent the system from entering a sleep state. This attribute is read-only. If the device is not enabled to - wake up the system from sleep states, this attribute is empty. + wake up the system from sleep states, this attribute is not + present. What: /sys/devices/.../power/wakeup_active Date: September 2010 @@ -115,7 +115,7 @@ Description: or 0, depending on whether or not a wakeup event associated with the device is being processed (1). This attribute is read-only. If the device is not enabled to wake up the system from sleep - states, this attribute is empty. + states, this attribute is not present. What: /sys/devices/.../power/wakeup_total_time_ms Date: September 2010 @@ -125,7 +125,7 @@ Description: the total time of processing wakeup events associated with the device, in milliseconds. This attribute is read-only. If the device is not enabled to wake up the system from sleep states, - this attribute is empty. + this attribute is not present. What: /sys/devices/.../power/wakeup_max_time_ms Date: September 2010 @@ -135,7 +135,7 @@ Description: the maximum time of processing a single wakeup event associated with the device, in milliseconds. This attribute is read-only. If the device is not enabled to wake up the system from sleep - states, this attribute is empty. + states, this attribute is not present. What: /sys/devices/.../power/wakeup_last_time_ms Date: September 2010 @@ -146,7 +146,7 @@ Description: signaling the last wakeup event associated with the device, in milliseconds. This attribute is read-only. If the device is not enabled to wake up the system from sleep states, this - attribute is empty. + attribute is not present. What: /sys/devices/.../power/autosuspend_delay_ms Date: September 2010 diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt index 57080cd74575..dd9b49251db3 100644 --- a/Documentation/power/devices.txt +++ b/Documentation/power/devices.txt @@ -159,18 +159,18 @@ matter, and the kernel is responsible for keeping track of it. By contrast, whether or not a wakeup-capable device should issue wakeup events is a policy decision, and it is managed by user space through a sysfs attribute: the power/wakeup file. User space can write the strings "enabled" or "disabled" to -set or clear the should_wakeup flag, respectively. Reads from the file will -return the corresponding string if can_wakeup is true, but if can_wakeup is -false then reads will return an empty string, to indicate that the device -doesn't support wakeup events. (But even though the file appears empty, writes -will still affect the should_wakeup flag.) +set or clear the "should_wakeup" flag, respectively. This file is only present +for wakeup-capable devices (i.e. devices whose "can_wakeup" flags are set) +and is created (or removed) by device_set_wakeup_capable(). Reads from the +file will return the corresponding string. The device_may_wakeup() routine returns true only if both flags are set. -Drivers should check this routine when putting devices in a low-power state -during a system sleep transition, to see whether or not to enable the devices' -wakeup mechanisms. However for runtime power management, wakeup events should -be enabled whenever the device and driver both support them, regardless of the -should_wakeup flag. +This information is used by subsystems, like the PCI bus type code, to see +whether or not to enable the devices' wakeup mechanisms. If device wakeup +mechanisms are enabled or disabled directly by drivers, they also should use +device_may_wakeup() to decide what to do during a system sleep transition. +However for runtime power management, wakeup events should be enabled whenever +the device and driver both support them, regardless of the should_wakeup flag. /sys/devices/.../power/control files |