title: Android device does not show up in adb list
body: <p>I have a HP Slate 21 that is connected to my Windows box using a USB cable. USB debugging is enabled on the device. After <a href="https://stackoverflow.com/a/15609366/3063884">adding the proper <code>%SingleAdbInterface%</code> and <code>%CompositeAdbInterface%</code></a> entries to the <code>android_winusb.inf</code> file, I now see "Android ADB Interface" in my Device Manager. However, running <code>adb devices</code> at the command-line does not show the device.</p>
  
  <p>I have another HP slate 7 that shows up just fine under <code>adb devices</code>.</p>
  
  <p>The only difference I see from Device Manager is that the one that works is named "Android Composite ADB Interface" and the other one is named "Android ADB Interface."</p>
  
  <p>There is yet another subtle difference. In the winusb.inf file, for Slate 7 I have two <code>%CompositeAdbInterface%</code> entries defined but for Slate 21, there is just one <code>%CompositeAdbInterface%</code> entry defined.</p>
  
  <p>What could be wrong with my setup?</p>