ddi_removing_power(9f)

1ddi_removing_power(9F)   Kernel Functions for Drivers   ddi_removing_power(9F)
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NAME

6       ddi_removing_power  -  check  whether DDI_SUSPEND might result in power
7       being removed from a device
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SYNOPSIS

10       #include <sys/ddi.h>
11       #include <sys/sunddi.h>
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15       int ddi_removing_power(dev_info_t *dip);
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INTERFACE LEVEL

19       Solaris DDI specific (Solaris DDI)
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DESCRIPTION

22       The ddi_removing_power() function indicates whether a currently pending
23       call  into a driver's detach(9E) entry point with a command of DDI_SUS‐
24       PEND is likely to result in power being removed from the device.
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27       ddi_removing_power() can return true and power  still  not  be  removed
28       from the device due to a failure to suspend and power off the system.
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PARAMETERS

31       The ddi_removing_power() function supports the following parameter:
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33       dip    pointer to the device's dev_info structure
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RETURN VALUES

37       The ddi_removing_power() function returns:
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39       1    Power might be removed by the framework as a result of the pending
40            DDI_SUSPEND call.
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43       0    Power will not be removed by the framework  as  a  result  of  the
44            pending DDI_SUSPEND call.
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EXAMPLES

48       Example 1 Protecting a Tape from Abrupt Power Removal
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51       A  tape driver that has hardware that would damage the tape if power is
52       removed might include this code in its detach(9E) code:
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55         int
56              xxdetach(dev_info_t *dip, ddi_detach_cmd_t cmd)
57              {
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59              ...
60                   case DDI_SUSPEND:
61                   /*
62                    * We do not allow DDI_SUSPEND if power will be removed and
63                    * we have a device that damages tape when power is removed
64                    * We do support DDI_SUSPEND for Device Reconfiguration,
65                    * however.
66                    */
67                      if (ddi_removing_power(dip) && xxdamages_tape(dip))
68                         return (DDI_FAILURE);
69                   ...
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ATTRIBUTES

73       See attributes(5) for descriptions of the following attributes:
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78       ┌─────────────────────────────┬─────────────────────────────┐
79       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
80       ├─────────────────────────────┼─────────────────────────────┤
81       │Interface Stability          │Committed                    │
82       └─────────────────────────────┴─────────────────────────────┘
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