Comment 4 for bug 1603558

Also I've tried 'virt-manager --debug' and adding USB Host Device. It seems output shows all is correct (http://pastebin.ubuntu.com/19548401/):

[сб, 16 лип 2016 00:21:58 virt-manager 26388] DEBUG (addhardware:124) Showing addhw
[сб, 16 лип 2016 00:22:14 virt-manager 26388] DEBUG (addhardware:1280) Running setup() for device=<virtinst.devicehostdev.VirtualHostDevice object at 0x7f92f40d2ed0>
[сб, 16 лип 2016 00:22:14 virt-manager 26388] DEBUG (addhardware:1282) Device setup() complete
[сб, 16 лип 2016 00:22:14 virt-manager 26388] DEBUG (addhardware:1295) Adding device:
<hostdev mode="subsystem" type="usb" managed="yes">
  <source>
    <vendor id="0x090c"/>
    <product id="0x1000"/>
  </source>
</hostdev>

[сб, 16 лип 2016 00:22:14 virt-manager 26388] DEBUG (domain:1014) attach_device with xml=
<hostdev mode="subsystem" type="usb" managed="yes">
  <source>
    <vendor id="0x090c"/>
    <product id="0x1000"/>
  </source>
</hostdev>

[сб, 16 лип 2016 00:22:14 virt-manager 26388] DEBUG (libvirtobject:74) Redefining <vmmDomain name=Kubuntu-16.04.x-x86_64-14GiB> with XML diff:
--- Original XML
+++ New XML
@@ -111,5 +111,11 @@
     <memballoon model="virtio">
       <address type="pci" domain="0x0000" bus="0x02" slot="0x06" function="0x0"/>
     </memballoon>
+ <hostdev mode="subsystem" type="usb" managed="yes">
+ <source>
+ <vendor id="0x090c"/>
+ <product id="0x1000"/>
+ </source>
+ </hostdev>
   </devices>
 </domain>

[сб, 16 лип 2016 00:22:14 virt-manager 26388] DEBUG (addhardware:134) Closing addhw

But anyway the device doesn't appeared in guest.