PATH ADC Home > Documentation > Hardware > Device Managers and Drivers > PCI Card Services > Designing PCI Cards and Drivers for Power Macintosh Computers

  

Modifying Open Firmware Config Variables From the Mac OS

The Name Registry provides a mechanism to save and restore device tree properties in NVRAM. This mechanism has been fully augmented in the NewWorld architecture. Using the same mechanism, Mac OS and Open Firmware driver software can update Open Firmware config variables in the device tree. The mechanism creates and modifies the device tree properties and the RegistryPropertySetMod function, using the kRegPropertyValueIsSavedToNVRAM modifier bit. When the Name Registry calls are made to the properties in the "device-tree:options" node, the corresponding Open Firmware config variables in NVRAM are modified.

For additional information about Name Registry properties, see Property Management. For information about the kRegPropertyValueIsSavedToNVRAM modifier bit, see Data Structures and Constants. For a description of the RegistryPropertySetMod function, see Property Modifier Retrieval and Assignment.

© 1999 Apple Computer, Inc. – (Last Updated 26 March 99)