The one thing I'm hoping for in every Linux kernel release is better support for Bluetooth and associated drivers. Besides some GPU issues, Bluetooth is the big thing preventing me from having a good consumer desktop experience on Linux.
I agree with you. Bluetooth works, but just barely, and it feels like it's getting worse.
Somewhere between 5.8 and 5.9 reconnecting became incredibly flaky for me (XPS 9300). Headphones will pair and connect fine the first time, but then completely fail to reconnect properly if I turn them off or walk out of range.
Sometimes I can connect to them again, but they don't get registered in pulseaudio, even after killing and restarting it.
Sometimes they will connect, then immediately disconnect again 5 seconds later (rinse and repeat until removed and repaired)
Sometimes they fail to connect entirely.
I end up consistently removing the device, restarting the bluetooth service, and then repairing fresh. In which case they work until the next disconnect.
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It's hardly the end of the world, and it's a little amazing that my biggest complaint about linux desktop these days is flaky bluetooth, but it's certainly annoying.
It used to work fine, and then at some point I stopped being able to disconnect and reconnect the same device without power cycling the computer.
I've also wondered if a lot of the bluetooth problems on Linux are actually caused by the desktop manager.
Most of the problems I've personally experienced have seemingly been tied to using old versions of Gnome on Ubuntu. In fact, Gnome in general has always been rough for me on bluetooth; the bluetooth connection app still needs some love, but I've noticed it being more reliable with recent versions. I particularly noticed this when I was running a newer version of Gnome on Fedora 31, but then running an older version of Gnome on Ubuntu 18.04 (for work). The older version of Gnome's bluetooth was considerably worse.
For about the past year, however, I've been using Fedora / KDE on desktop and OpenSUSE / KDE on my laptop. This has been by far the best bluetooth experience I've had on Linux. Thank you to whoever wrote the KDE bluetooth code, because it is consistent and reliable.
So I don't think it is totally a kernel problem. YMMV depending on what cards/adapters you're using (I'm using a mix of Intel and some USB sticks from a fly-by-night vendor).
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)
Saying that it's hard to get through is an understatement.
I can say I can let this pass if the maintainer was really an overworked volunteer who shared his work on Linux with his day job, but not if the guy works for the biggest electronics company in the world.
I believe Linux core devs need to put stricter criteria on system maintainers if they are working on company's payroll.