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Diffstat (limited to 'Documentation/ABI')
-rw-r--r-- | Documentation/ABI/testing/sysfs-power | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power index 2875f1f74a0..194ca446ac2 100644 --- a/Documentation/ABI/testing/sysfs-power +++ b/Documentation/ABI/testing/sysfs-power | |||
@@ -99,9 +99,38 @@ Description: | |||
99 | 99 | ||
100 | dmesg -s 1000000 | grep 'hash matches' | 100 | dmesg -s 1000000 | grep 'hash matches' |
101 | 101 | ||
102 | If you do not get any matches (or they appear to be false | ||
103 | positives), it is possible that the last PM event point | ||
104 | referred to a device created by a loadable kernel module. In | ||
105 | this case cat /sys/power/pm_trace_dev_match (see below) after | ||
106 | your system is started up and the kernel modules are loaded. | ||
107 | |||
102 | CAUTION: Using it will cause your machine's real-time (CMOS) | 108 | CAUTION: Using it will cause your machine's real-time (CMOS) |
103 | clock to be set to a random invalid time after a resume. | 109 | clock to be set to a random invalid time after a resume. |
104 | 110 | ||
111 | What; /sys/power/pm_trace_dev_match | ||
112 | Date: October 2010 | ||
113 | Contact: James Hogan <james@albanarts.com> | ||
114 | Description: | ||
115 | The /sys/power/pm_trace_dev_match file contains the name of the | ||
116 | device associated with the last PM event point saved in the RTC | ||
117 | across reboots when pm_trace has been used. More precisely it | ||
118 | contains the list of current devices (including those | ||
119 | registered by loadable kernel modules since boot) which match | ||
120 | the device hash in the RTC at boot, with a newline after each | ||
121 | one. | ||
122 | |||
123 | The advantage of this file over the hash matches printed to the | ||
124 | kernel log (see /sys/power/pm_trace), is that it includes | ||
125 | devices created after boot by loadable kernel modules. | ||
126 | |||
127 | Due to the small hash size necessary to fit in the RTC, it is | ||
128 | possible that more than one device matches the hash, in which | ||
129 | case further investigation is required to determine which | ||
130 | device is causing the problem. Note that genuine RTC clock | ||
131 | values (such as when pm_trace has not been used), can still | ||
132 | match a device and output it's name here. | ||
133 | |||
105 | What: /sys/power/pm_async | 134 | What: /sys/power/pm_async |
106 | Date: January 2009 | 135 | Date: January 2009 |
107 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | 136 | Contact: Rafael J. Wysocki <rjw@sisk.pl> |