Registry Keys Used by the Device Manager

The Device Manager uses registry keys stored in the HKEY_LOCAL_MACHINE\Drivers\ key. The following are the major subkeys of the HKEY_LOCAL_MACHINE\Drivers\ key:

Active\

The Active\ key contains subkeys that track currently active drivers loaded by the Device Manager. Device driver setup routines should not modify the Active\ key’s contents, nor should they rely on the presence of any specific values within the Active\ key.

When a device driver is loaded, the Device Manager passes it the path to its Active\ key as the dwContext parameter in the device driver’s XXX_Init function. The device driver can rely on the presence of the following values:

• Hnd

  Device handle from the RegisterDevice function

• Name

  Device file name

• Key

  Registry path within HKEY_LOCAL_MACHINE to the device driver key

The Active\ key for PC Card device drivers has the following additional values:

• PnpId

  Plug and Play identifier string

• Sckt

  Current socket and function pair of the PC Card

Once a device driver is loaded, it can add values to its Active\ key. However, the Device Manager deletes the device driver Active\ key and any values in it when the device driver is unloaded.

Builtin\

The Builtin\ key contains subkeys that govern stream interface driver DLLs provided by the manufacturer of a Windows CE–based platform. As stated, OEMs can implement drivers for certain types of built-in devices, using the stream interface driver model.

PCMCIA\

The PCMCIA\ key contains subkeys related to PC Cards and their stream interface drivers. The most important information in these subkeys is the Plug and Play identifier of the PC Card, which corresponds to a specified driver.

Detect\

The Detect\ subkey contains numbered entries that list DLL names and detection functions. The functions identify a generic stream interface driver for PC Cards with no Plug and Play identifier or PC Cards with an unknown Plug and Play identifier. For more information, see Drivers\PCMCIA\Detect.

Driver

Driver subkeys, named after generic PC Card drivers, contain values used to load the drivers. The Device Manager creates individual Driver subkeys when a generic stream interface driver detection function indicates that it can drive a particular device. The existence of a Driver subkey indicates detection by a driver that has an entry within the PCMCIA\Detect\ key.

Plug-and-Play ID

Plug-and-Play ID subkeys contain values used to load stream interface drivers for PC Cards. Typically, the setup routine for a PC Card driver creates these subkeys when the driver is installed on a platform.