Puoi ottenere un elenco di power assertion eseguendo pmset -g assertions
:
$ pmset -g assertions
10/27/13, 8:48:55 AM GMT
Assertion status system-wide:
BackgroundTask 1
PreventDiskIdle 0
ApplePushServiceTask 0
UserIsActive 0
PreventUserIdleDisplaySleep 0
InteractivePushServiceTask 0
PreventSystemSleep 0
ExternalMedia 1
InternalPreventDisplaySleep 1
PreventUserIdleSystemSleep 1
NetworkClientActive 0
Listed by owning process:
pid 189(coreaudiod): [0x0000000100000617] 00:00:19 NoIdleSleepAssertion named: "com.apple.audio.'AppleHDAEngineOutput:1B,0,1,2:0'.noidlesleep"
pid 9879(backupd): [0x00000001000005f1] 00:13:17 PreventUserIdleSystemSleep named: "Time Machine backup"
pid 9879(backupd): [0x0000000c000005f0] 00:13:17 BackgroundTask named: "Time Machine backup"
pid 18(powerd): [0x00000009000005e1] 00:13:47 ExternalMedia named: "com.apple.powermanagement.externalmediamounted"
pid 18(powerd): [0x00000011000002e1] 00:00:00 InternalPreventDisplaySleep named: "com.apple.powermanagement.delayDisplayOff"
Timeout will fire in 299 secs Action=TimeoutActionTurnOff
Kernel Assertions: 0x4=USB
id=500 level=255 0x4=USB mod=10/26/13, 6:38 PM description=XHC1 owner=AppleUSBXHCI
id=501 level=255 0x4=USB mod=10/26/13, 6:45 PM description=EHC2 owner=AppleUSBEHCI
id=502 level=255 0x4=USB mod=10/27/13, 8:48 AM description=EHC1 owner=AppleUSBEHCI
Nell'output precedente, Time Machine sta impedendo la sospensione del periodo di inattività.