Enable MIDI support

[wvengen]

Now that bluez has landed with 5.46-0ubuntu2, it would be nice to enable Bluetooth MIDI support. This did not seem to be enabled by default in the build from https://launchpad.net/ubuntu/+source/bluez/5.46-0ubuntu2 (it found BLE MIDI devices, gatttool could talk to them, but no MIDI device was made; also ldd showed no linkage to libasound.so.2).

After recompiling it with libasound2-dev installed and --enable-midi in debian/rules, it worked.

Suggestion: add libasound2-dev to bluez dependencies, add --enable-midi to rules.

[Daniel van Vugt (vanvugt)]

Very interesting suggestion. Yes I think we should do this. Since it's a feature rather than a bug though, we would either need to request an exception to get it into 17.10, or wait till 18.04.

[wvengen (wvengen)]

Thanks, I agree that 18.04 would be good.

[wvengen (wvengen)]

For those seeking a workaround, see instructions here: https://gist.github.com/wvengen/7ebd29da38c08540832fb228c4628171#bluez-546

[Andrew M (primary-edw)]

Any chance this could be added? I know the last message is from 2017, but there commercial products such as the Yamaha MD-BT01 Bluetooth Wireless MIDI Adaptor that rely on this being enabled.

[korakios (korakios667)]

I tried the latest version (5.50) from

https://launchpad.net/~bluetooth/+archive/ubuntu/bluez

without success. Is bluetooth midi completely disabled on Ubuntu?

[Sebastien Bacher (seb128)]

The option is off by default in the upstream build see
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/README#n252

Since the option is flagged experimental by upstream it doesn't seem like something we want to enable in Ubuntu yet

[Horst Baerbel (horstbaerbel)]

I have that problem on an Ubuntu 19.10 box. I tried to connect an ESP32 using BLE to act as a MIDI device. The device is detected and can be paired, but no MIDI device is created. It would be good to have this enabled.

[Henning Sprang (henning)]

as far as I can see in the bluez package source, the midi option is enabled now, so it *could* be closed...

But even though it's on, I dont get it working, so I cannot confirm for sure.

Expectation is: when connecting to a device, I get an alsa sequencer client, but I dont see that happening.

But also I am not sure if I use it correctly, as i see nearly no documentation about it, despite one place that said what I mentioned above in what I expect to happen.
I dont even know for sure if this direction is supposed to be unidirectional or bi-directional. (e.g. if my laptop can be the midi host, device or both).

I'll keep trying. If anyone has a pointer to docs how it is really supposed to work, so i can confirm, it would be helpful and this ticket could be closed.

[wvengen (wvengen)]

@henning that sounds great! In which version did you see this? I expect the build would also need the libasound2-dev dependency, which should be in the control file.

I remember that indeed an alsa sequencer device was created on connection; I only tested (when submitting this bug) midi controllers that provided midi notes, which could drive a drum synth (not the other direction), but I'd expect both directions to work.

[wvengen (wvengen)]

As far as I can see, it is still disabled by default [in kernel bluez](https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/configure.ac#n243) nor [in launchpad](https://git.launchpad.net/bluez/tree/configure.ac#n239), neither do I find in being enabled explicitely in a package (but could not so easily find the package code online).