[solved] BT dongle to pass through to win10


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[solution below]

Started using unraid again after couple of years. Updated the OS and windows 10 VM, but bluetooth dongle no longer works.

It's detected by VM, but it connects to couple of minutes max, after which device is no longer functioning (might state "Connected" in win bluetooth settings though).


Have tried 3 different devices:

- onboard BT module (Asrock's Fatal1ty Z170 mobo), think it's BCM20702A0 chipset;
- plugable USB dongle (should be same chipset as above)
- CSR dongle (unknown chipset, but this is the one that used to work before)


Have tried all of these 3 devices, but best I can do is connect the keyboard for 1-2 minutes, after which it no longer works. It never pairs again.


Any pointers? Things worked relatively well around v6.4. Of course windows was also at lower ver back in those days, hard to tell where the issue is here really.


If these products/chipsets are no-go, can you recommend one that should be compatible with latest unraid/win10 vm?


Edit: tried old backed up VM images, and those fail to work as well. Maybe it's something that newer unraid versions are interfering with?
Edit2: appears to be similar to this:

One thing I've noticed - if I keep the "add new device" dialog open, then the device is kept connected. As soon as the dialog is closed and you stop typing on BT keyboard for ~3sec, the pairing is lost. Looks like it requires active communication over BT to keep it running.


Running unraid v 6.8.3



The problem wasn't unraid upgrade, but windows upgrade for the VM.

To get this sudden disconnection issue resolved, you need to open Device Manager, open the dialog for your bluetooth device, select 'Power Management' tab, and untick the 'allow this device to be powered off...' box.

Problem for me was that the Win10 build I installed (build 2004) didn't have that checkbox available for my bluetooth device anymore.

So the solution is to either
a) continue using older windows builds that still have said tickbox; or
b) get a bluetooth USB dongle and connect it into USB controller that's passed through.

Note for b) you might also want to go through the listed 'USB device' & USB controllers in Device Manager, and uncheck the same power management feature.

Edited by tuxbass
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  • 4 months later...

I recently ran into this problem on a motherboard with no spare USB controllers or free PCIe slots so buying an expansion card or passing an existing controller through to the VM was not an option. In my case, I noticed that as long as the Bluetooth dongle was kept active all connected devices would remain attached and usable. I "solved" the issue in the Windows VM by running a Bluetooth scanning program which would constantly keep the Bluetooth connection active. I configured the scanner to run in the background as a Windows service which is kicked off on the login screen so that I am able to use my bluetooth keyboard and mouse to login to the VM.

This is the bluetooth scanning software I am using: https://www.nirsoft.net/utils/bluetooth_log_view.html
This solution was inspired by the following reddit post: https://www.reddit.com/r/VFIO/comments/hiwc5u/onboard_usb_bluetooth_passed_to_windows_10_guest/


For me, this solution is acceptable but suboptimal. I would prefer to find some way of fixing the underlying bluetooth-specific disconnect problems that occur when directly passing the dongle through to the VM. I have tried many approaches but am still hopeful there may be some VFIO options that could help.

Symptoms of the original problem

In my case, I also noticed that the bluetooth connection stopped responding to new events after a few seconds of inactivity but any existing events would still be processed. More specifically, on my bluetooth keyboard if I pressed and held down a key then a "key down event" would be sent and text would appear on screen but if I failed to lift my finger within ~3seconds the corresponding "key up event" would not be received and the VM would behave as though I was still pressing the key until I turned off bluetooth entirely. 

Edited by pants
Clarify that final paragraph applies to original problem and does not appear after solution has been implemented
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