Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions
Privacy Policy

  




 

 

Writing Device Drivers
Previous Next

Changes to Power Management Interfaces

Prior to the Solaris 8 release, power management of devices was not automatic. Developers had to add an entry to /etc/power.conf for each device that was to be power-managed. The framework assumed that all devices supported only two power levels: 0 and standard power.

Power assumed an implied dependency of all other components on component 0. When component 0 changed to level 0, a call was made into the driver's detach(9E) with the DDI_PM_SUSPEND command to save the hardware state. When component 0 changed from level 0, a call was made to the attach(9E) routine with the command DDI_PM_RESUME to restore hardware state.

The following interfaces and commands are obsolete, although they are still supported for binary purposes:

  • ddi_dev_is_needed(9F)

  • pm_create_components(9F)

  • pm_destroy_components(9F)

  • pm_get_normal_power(9F)

  • pm_set_normal_power(9F)

  • DDI_PM_SUSPEND

  • DDI_PM_RESUME

Since the Solaris 8 release, devices that export the pm-components property automatically use power management if autopm is enabled.

The framework now knows from the pm-components property which power levels are supported by each device.

The framework makes no assumptions about dependencies among the different components of a device. The device driver is responsible for saving and restoring hardware state as needed when changing power levels.

These changes enable the power management framework to deal with emerging device technology. Power management now results in greater power savings. The framework can detect automatically which devices can save power. The framework can use intermediate power states of the devices. A system can now meet energy consumption goals without powering down the entire system and without any functions.

Table 12-1 Power Management Interfaces

Removed Interfaces

Equivalent Interfaces

pm_create_components(9F)

pm-components(9P)

pm_set_normal_power(9F)

pm-components(9P)

pm_destroy_components(9F)

None

pm_get_normal_power(9F)

None

ddi_dev_is_needed(9F)

pm_raise_power(9F)

None

pm_lower_power(9F)

None

pm_power_has_changed(9F)

DDI_PM_SUSPEND

None

DDI_PM_RESUME

None

Previous Next

 
 
  Published under the terms fo the Public Documentation License Version 1.01. Design by Interspire