Re: [gentoo-user] Bluetooth disappeared because of MSWindows?

[Alan McKinnon <alan.mckinnon@gmail.com>]

On 06/12/2015 01:31, Mick wrote:
> I came across a rather peculiar phenomenon today with my laptop.  I realised 
> that my bluetooth controller was nowhere to be found.  I thought running 
> hciconfig would bring it up, but all it did was to complain that there was no 
> device found.  rfkill would not list it either.
> 
> Modprobing various modules did not produce a device, so searching for answers 
> I thought of booting into MSWindows.  After I enabled the device in MSWindows 
> I rebooted into Linux and was surprised to see the bluetooth controller was 
> visible again in lspci.
> 
> How come that switching off the device in one OS, affects the other?  :-/
> 
> What should I do next time to enable bluetooth from within Linux?
> 
> 
> PS. There's a parallel to this with the same laptop.  Some years ago audio 
> would randomly never come up at boot and no amount of alsactl could wake it 
> up.  A swift reboot into MSWindows would reset audio and all would work fine 
> in Linux thereafter.  Some cursory troubleshooting at the time didn't help me 
> much.  I don't expect that the two issues are related, but thought of 
> mentioning it just in case.
> 


We've had a few cases of things like this on the list over the years. It
always end up probably a Linux driver bug. Here's what seems to happen:

The hardware needs to be enabled/shutdown/fiddled or whatever in some
magic way that windows knows about but linux doesn't. Booting into
Windows applies the magic so when you reboot into Linux it's now in a
state Linux can use.

Read the kernel docs for your driver, the odds are good you have to
apply a driver tweak for your hardware to make it work right.

Then do a Google search for your hardware and laptop types, see what the
interwebz have to say.

-- 
Alan McKinnon
alan.mckinnon@gmail.com