diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-power')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-power | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power index d882f8093871..dcff4d0623ad 100644 --- a/Documentation/ABI/testing/sysfs-power +++ b/Documentation/ABI/testing/sysfs-power | |||
| @@ -21,7 +21,7 @@ Description: | |||
| 21 | these states. | 21 | these states. |
| 22 | 22 | ||
| 23 | What: /sys/power/disk | 23 | What: /sys/power/disk |
| 24 | Date: August 2006 | 24 | Date: September 2006 |
| 25 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | 25 | Contact: Rafael J. Wysocki <rjw@sisk.pl> |
| 26 | Description: | 26 | Description: |
| 27 | The /sys/power/disk file controls the operating mode of the | 27 | The /sys/power/disk file controls the operating mode of the |
| @@ -39,6 +39,19 @@ Description: | |||
| 39 | 'reboot' - the memory image will be saved by the kernel and | 39 | 'reboot' - the memory image will be saved by the kernel and |
| 40 | the system will be rebooted. | 40 | the system will be rebooted. |
| 41 | 41 | ||
| 42 | Additionally, /sys/power/disk can be used to turn on one of the | ||
| 43 | two testing modes of the suspend-to-disk mechanism: 'testproc' | ||
| 44 | or 'test'. If the suspend-to-disk mechanism is in the | ||
| 45 | 'testproc' mode, writing 'disk' to /sys/power/state will cause | ||
| 46 | the kernel to disable nonboot CPUs and freeze tasks, wait for 5 | ||
| 47 | seconds, unfreeze tasks and enable nonboot CPUs. If it is in | ||
| 48 | the 'test' mode, writing 'disk' to /sys/power/state will cause | ||
| 49 | the kernel to disable nonboot CPUs and freeze tasks, shrink | ||
| 50 | memory, suspend devices, wait for 5 seconds, resume devices, | ||
| 51 | unfreeze tasks and enable nonboot CPUs. Then, we are able to | ||
| 52 | look in the log messages and work out, for example, which code | ||
| 53 | is being slow and which device drivers are misbehaving. | ||
| 54 | |||
| 42 | The suspend-to-disk method may be chosen by writing to this | 55 | The suspend-to-disk method may be chosen by writing to this |
| 43 | file one of the accepted strings: | 56 | file one of the accepted strings: |
| 44 | 57 | ||
| @@ -46,6 +59,8 @@ Description: | |||
| 46 | 'platform' | 59 | 'platform' |
| 47 | 'shutdown' | 60 | 'shutdown' |
| 48 | 'reboot' | 61 | 'reboot' |
| 62 | 'testproc' | ||
| 63 | 'test' | ||
| 49 | 64 | ||
| 50 | It will only change to 'firmware' or 'platform' if the system | 65 | It will only change to 'firmware' or 'platform' if the system |
| 51 | supports that. | 66 | supports that. |