[AC97SMPL.AddReg]
This section is an add-registry-section, whose entries satisfy the following format :

[add-registry-section]
reg-root, [subkey], [value-entry-name], [flags], [value]

An HKR specification in such an add-registry section designates the ..Class\{SetupClassGUID}\device-instance-id registry path to the user-accessible driver (a.k.a. "software" key).

Processing this section will add into the registry under HKR the following values :

AssociatedFilters

Description : used to load additional drivers (sys files) needed to enable the whole range of wdm features of the hardware device.
Location : HKR
Subkey : (null) current subkey
Value-entry name : AssociatedFilters
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : "wdmaud, swmidi, redbook"

Driver

Description : specifies the driver file of the device.
Location : HKR
Subkey : (null) current subkey
Value-entry name : Driver
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : AC97SMPL.sys

NTMPDriver

Description : denominates (a) NT MiniPort driver file(s).
Location : HKR
Subkey : (null) current subkey
Value-entry name : NTMPDriver
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : "AC97SMPL.sys, sbemul.sys"

SubClasses

Description : specifies the type of functionality the driver offers.
Location : HKR
Subkey : Drivers (subkey of the crt key, will be created if needed)
Value-entry name : SubClasses
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : "wave, midi, mixer"

Wave Driver

Description : specifies the driver to be used for the wave subclass.
Location : HKR
Subkey : Drivers\wave\wdmaud.drv
Value-entry name : Driver
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : wdmaud.drv

MIDI Driver

Description : specifies the driver to be used for the midi subclass.
Location : HKR
Subkey : Drivers\midi\wdmaud.drv
Value-entry name : Driver
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : wdmaud.drv

Mixer Driver

Description : specifies the driver to be used for the mixer subclass.
Location : HKR
Subkey : Drivers\mixer\wdmaud.drv
Value-entry name : Driver
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : wdmaud.drv

Wave Description

Description : description of the wave subclass.
Location : HKR
Subkey : Drivers\wave\wdmaud.drv
Value-entry name : Description
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : %AC97SMPL.DeviceDesc%

MIDI Description

Description : description of the midi subclass.
Location : HKR
Subkey : Drivers\midi\wdmaud.drv
Value-entry name : Description
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : %AC97SMPL.DeviceDesc%

Mixer Description

Description : description of the mixer subclass.
Location : HKR
Subkey : Drivers\midi\wdmaud.drv
Value-entry name : Description
Value-entry type : szString (default value, FLG_ADDREG_TYPE_SZ = 0x00000000)
Value : %AC97SMPL.DeviceDesc%

The string token used is defined in the Strings sections of the INF :

[Strings]
...
AC97SMPL.DeviceDesc="AC'97 Sample Driver for Intel(r) 82801 Controller"

and its localized version :

[Strings.0407]
...
AC97SMPL.DeviceDesc="AC'97 Treiberbeispiel für Intel(r) 82801 Kontroller"

See also the Glossary entry for AddReg.