title: Do extension Inf's files, do they inherit the class that there attached to
body: <p><strong>Question</strong> - Do extension Inf's files, do they inherit the class that there attached to.</p>
  <p><strong>EX</strong> - if i have a USBVideo class, can i add values to the [USBVideo.HW.AddReg] section</p>
  <p>So i was trying to extend a USB UVC camera with a INF extension file.  I grabbed the example here and it <a href="https://learn.microsoft.com/en-us/windows-hardware/drivers/install/using-an-extension-inf-file#example-1-using-an-extension-inf-to-set-the-device-friendly-name" rel="nofollow noreferrer">got it</a> to work.  I added a friendly name to a existing camera.</p>
  <p>Then i wanted to add these registers to my inf file but they didn't seem to take.  This is what my extension inf file looked like.  I also tried to add them to the [USBVideo] section like a different <a href="https://learn.microsoft.com/en-us/windows-hardware/drivers/stream/uvc-camera-implementation-guide#sensor-cameras" rel="nofollow noreferrer">example suggested</a>.  All the new code i added didn't seem to add a register in the HKEY_LOCAL_MACHINE -&gt; system-&gt; currentCotnrolSet-&gt;Enum  section of the device.</p>
  <pre class="lang-cpp prettyprint-override"><code>[Version]
  Signature   = &quot;$WINDOWS NT$&quot;
  Class       = Extension
  ClassGuid   = {e2f84ce7-8efa-411c-aa69-97454ca4cb57}
  Provider    = %CONTOSO%
  ExtensionId = {zzzzzzzz-zzzz-zzzz-zzzz-zzzzzzzzzzzz} ; replace with your own GUID
  DriverVer   = 05/28/2013,1.0.0.0
  CatalogFile = delta.cat
  PnpLockdown = 1
  
  [Manufacturer]
  %CONTOSO% = DeviceExtensions,NTamd64
  
  [DeviceExtensions.NTamd64]
  %Device.ExtensionDesc% = DeviceExtension_Install, PCI\VEN_XXXX&amp;DEV_XXXX&amp;SUBSYS_XXXXXXXX&amp;REV_XXXX
  
  [DeviceExtension_Install]
  ; No changes
  
  [DeviceExtension_Install.HW]
  AddReg = FriendlyName_AddReg
  AddReg=USBVideo.HW.AddReg ; new code
  
  [FriendlyName_AddReg]
  HKR,,FriendlyName,, &quot;New Device Friendly Name&quot;
  
  ;;;;;;;;;;;;;;;;;;New code
  HKR,, SensorCameraMode, 0x00010001,1      ; places the value under device HW
                                            ; Registry key
  
  HKR,, SkipCameraEnumeration, 0x00010001,1 ; This makes the camera available
                                            ; only for application looking for
                                            ; IR cameras
  
  ; same file's as above just in a different section for testing purposes  
  [USBVideo.HW.AddReg]
  HKR,, SensorCameraMode, 0x00010001,1      ; places the value under device HW
                                            ; Registry key
  
  HKR,, SkipCameraEnumeration, 0x00010001,1 ; This makes the camera available
                                            ; only for application looking for
                                            ; IR cameras
  
  ;;;;;;;;;;;;;;;;;;End of new code
  
  [Strings]
  CONTOSO              = &quot;Contoso&quot;
  Device.ExtensionDesc = &quot;Sample Device Extension&quot;
  
  </code></pre>