title: bluetoothctl No default controller available
body: <p>It's a bit wired here.</p>
  <p>I have a problem is bluetoothctl always said &quot;No default controller available&quot;. I found there are many people had same problem with me. But the situation is a bit different from them.</p>
  <p>I can see my hciconfig -a have information like below<br />
  <img src="https://i.stack.imgur.com/02Hpa.png" alt="enter image description here" /></p>
  <p>And hcitool dev seems no problem as well.<br />
  <img src="https://i.stack.imgur.com/8oIZY.png" alt="enter image description here" /></p>
  <p>But I have no idea why my bluetoothctl always said &quot;No default controller available&quot;<br />
  <img src="https://i.stack.imgur.com/Xs8JI.png" alt="enter image description here" /></p>
  <p>Even when I turn down and turn up hci0 several times. It always in the same problem.</p>
  <p>BTW, my BlueZ is 5.39.  And I tried this experiment on buildroot. Kernel is 3.10</p>