pm(9p) - osol9

1pm(9P)                   Kernel Properties for Drivers                  pm(9P)
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NAME

6       pm - Power Management properties
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DESCRIPTION

9       The pm-hardware-state property can be used to influence the behavior of
10       the Power  Management  framework.  Its  syntax  and  interpretation  is
11       described below.
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14       Note  that  this property is only interpreted by the system immediately
15       after the device has successfully attached.  Changes  in  the  property
16       made  by  the  driver  after the driver has attached will not be recog‐
17       nized.
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20       pm-hardware-state is a string-valued property. The existence of the pm-
21       hardware-state  property indicates that a device needs special handling
22       by the Power Management framework with regard to its hardware state.
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25       If the value of this property is needs-suspend-resume, the device has a
26       hardware  state  that cannot be deduced by the framework. The framework
27       definition of a device with hardware state is one with a reg  property.
28       Some  drivers, such as SCSI disk and tape drivers, have no reg property
29       but manage devices with "remote" hardware. Such a device  must  have  a
30       pm-hardware-state property with a value of needs-suspend-resume for the
31       system to identify it as needing a call to its detach(9E)  entry  point
32       with  command  DDI_SUSPEND  when  system  is  suspended,  and a call to
33       attach(9E) with command DDI_RESUME when system is resumed. For  devices
34       using  original  Power  Management  interfaces (which are now obsolete)
35       detach(9E) is also called with DDI_PM_SUSPEND before power  is  removed
36       from  the  device,  and  attach(9E)  is called with DDI_PM_RESUME after
37       power is restored.
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40       A value of no-suspend-resume indicates that, in spite of the  existence
41       of a reg property, a device has no hardware state that needs saving and
42       restoring. A device exporting this property will not have its  detach()
43       entry  point  called with command DDI_SUSPEND when system is suspended,
44       nor will its attach() entry point be  called  with  command  DDI_RESUME
45       when  system  is resumed. For devices using the original (and now obso‐
46       lete) Power Management interfaces, detach(9E) will not be  called  with
47       DDI_PM_SUSPEND  command  before  power  is removed from the device, nor
48       attach(9E) will be called with DDI_PM_RESUME  command  after  power  is
49       restored to the device.
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52       A  value  of parental-suspend-resume indicates that the device does not
53       implement  the  detach(9E)  DDI_SUSPEND  semantics,  nor  the  attach()
54       DDI_RESUME semantics, but that a call should be made up the device tree
55       by the framework to effect the  saving  and/or  restoring  of  hardware
56       state  for  this  device.  For  devices using original Power Management
57       interfaces (which are now obsolete), it also indicates that the  device
58       does  not  implement  the  detach(9E) DDI_PM_SUSPEND semantics, nor the
59       attach(9E) DDI_PM_RESUME semantics, but that a call should be  made  up
60       the  device tree by the framework to effect the saving and/or restoring
61       the hardware state for this device.
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ATTRIBUTES

64       See attributes(5) for descriptions of the following attributes:
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69       ┌─────────────────────────────┬─────────────────────────────┐
70       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
71       ├─────────────────────────────┼─────────────────────────────┤
72       │Interface stability          │Committed                    │
73       └─────────────────────────────┴─────────────────────────────┘
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NAME

DESCRIPTION

ATTRIBUTES

SEE ALSO