I have Bluetooth 4.1 built into my WiFi card, over the last year the only issue I have had was manually having to switch to HSP mode on my headphones to use the Mic. Switching from A2DP to HSP was easy, just click Audio in the settings menu in the upper right corner in Gnome.
Besides that, Bluetooth mice and headphones &keyboards just work.
That said, the replacement process is pretty fiddly...Dell likes using lots of very small screws made of very soft metal.
I've also found that Gnome's bluetooth handling varies from barely acceptable to confusingly horrible. KDE's bluetooth handling has been way more reliable for me across multiple machines and distros. So the problem may very well be in userspace.
I don't really use BT for anything, so I can't comment on its quality. WiFi has been completely fine, though. Either way, I believe both the WiFi and BT hardware are soldered in on this model.
(from https://wiki.archlinux.org/index.php/Bluetooth_headset#Switc...)
That discusses audio flowing in both directions.
> Each A2DP service, of possibly many, is designed to uni-directionally transfer an audio stream in up to 2 channel stereo, either to or from the Bluetooth host.
This matches what I has heard: Bluetooth devices with A2DP profile can either receive or send high-quality audio, but not both at the same time.
I don't know if there are Bluetooth headsets that have separate A2DP devices for input and output sound, I have never heard about them, but I would be very interested in knowing of their existence.
Also from the article:
> These systems often also implement Headset (HSP) or Hands-Free (HFP) profiles for telephone calls, which may be used separately.
This is the common case for Bluetooth headsets, the Bluetooth manager switches profile when the microphone is needed, but that greatly reduces audio quality.
When I am using the headphones, and IF an application requests microphone, THEN I do want this switch to happen automatically. After the Microphone is not needed anymore, I want it to switch back to the HQ A2DP.
Am I missing something here?
But how else would my mic work? If it stays on A2DP, then there is no Mic input, so I used to have to manually switch it to HSP. With the solution I linked above, this is not manual.
So... I am not sure it does support it, TBH. I have a Bose QuietComfort 35 (II), and on linux I definitely have the low quality HSP+ mic (other thatn the quality, works well) and for listening only, A2DP is working too.
On Android though, calls are _MUCH_ higher quality with the mic on. (still somewhat different than from output-only, but less degradation than under my desktop linux)