POWER(9E)POWER(9E)NAMEpower - power a device attached to the system
SYNOPSIS
#include <sys/ddi.h>
#include <sys/sunddi.h>
int prefixpower(dev_info_t *dip, int component, int level);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI). This entry point is required. If
the driver writer does not supply this entry point, the value NULL must
be used in the cb_ops(9S) structure instead.
PARAMETERS
dip
Pointer to the device's dev_info structure.
component
Component of the driver to be managed.
level
Desired component power level.
DESCRIPTION
The power(9E) function is the device-specific Power Management entry
point. This function is called when the system wants the driver to set
the power level of component to level.
The level argument is the driver-defined power level to which the com‐
ponent needs to be set. Except for power level 0, which is interpreted
by the framework to mean "powered off," the interpretation of level is
entirely up to the driver.
The component argument is the component of the device to be power-man‐
aged. The interpretation of component is entirely up to the driver.
When a requested power transition would cause the device to lose state,
the driver must save the state of the device in memory. When a
requested power transition requires state to be restored, the driver
must restore that state.
If a requested power transition for one component requires another com‐
ponent to change power state before it can be completed, the driver
must call pm_raise_power(9F) to get the other component changed, and
the power(9E) entry point must support being re-entered.
If the system requests an inappropriate power transition for the device
(for example, a request to power down a device which has just become
busy), then the power level should not be changed and power should
return DDI_FAILURE.
RETURN VALUES
The power() function returns:
DDI_SUCCESS
Successfully set the power to the requested level.
DDI_FAILURE
Failed to set the power to the requested level.
CONTEXT
The power() function is called from user or kernel context only.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface stability │ Committed │
└────────────────────┴─────────────────┘
SEE ALSOattach(9E), detach(9E), pm_busy_component(9F), pm_idle_component(9F),
pm_raise_power(9F), cb_ops(9S)
Writing Device Drivers
Using Power Management
Dec 12, 2003 POWER(9E)
