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Diffstat (limited to 'Documentation/ABI/testing/sysfs-power')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-power | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power index d6a801f45b4..194ca446ac2 100644 --- a/Documentation/ABI/testing/sysfs-power +++ b/Documentation/ABI/testing/sysfs-power @@ -99,9 +99,38 @@ Description: dmesg -s 1000000 | grep 'hash matches' + If you do not get any matches (or they appear to be false + positives), it is possible that the last PM event point + referred to a device created by a loadable kernel module. In + this case cat /sys/power/pm_trace_dev_match (see below) after + your system is started up and the kernel modules are loaded. + CAUTION: Using it will cause your machine's real-time (CMOS) clock to be set to a random invalid time after a resume. +What; /sys/power/pm_trace_dev_match +Date: October 2010 +Contact: James Hogan <james@albanarts.com> +Description: + The /sys/power/pm_trace_dev_match file contains the name of the + device associated with the last PM event point saved in the RTC + across reboots when pm_trace has been used. More precisely it + contains the list of current devices (including those + registered by loadable kernel modules since boot) which match + the device hash in the RTC at boot, with a newline after each + one. + + The advantage of this file over the hash matches printed to the + kernel log (see /sys/power/pm_trace), is that it includes + devices created after boot by loadable kernel modules. + + Due to the small hash size necessary to fit in the RTC, it is + possible that more than one device matches the hash, in which + case further investigation is required to determine which + device is causing the problem. Note that genuine RTC clock + values (such as when pm_trace has not been used), can still + match a device and output it's name here. + What: /sys/power/pm_async Date: January 2009 Contact: Rafael J. Wysocki <rjw@sisk.pl> @@ -114,3 +143,18 @@ Description: if this file contains "1", which is the default. It may be disabled by writing "0" to this file, in which case all devices will be suspended and resumed synchronously. + +What: /sys/power/wakeup_count +Date: July 2010 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/power/wakeup_count file allows user space to put the + system into a sleep state while taking into account the + concurrent arrival of wakeup events. Reading from it returns + the current number of registered wakeup events and it blocks if + some wakeup events are being processed at the time the file is + read from. Writing to it will only succeed if the current + number of wakeup events is equal to the written value and, if + successful, will make the kernel abort a subsequent transition + to a sleep state if any wakeup events are reported after the + write has returned. |