Bluetooth broken in recent master? [workaround]

I run my laptop on the unstable channel, and I use a Bluetooth Low Energy keyboard. It seems that recent changes cause my keyboard to no longer connect. Bluetooth works fine and sees new devices but not my already-paired keyboard.

I did some upgrades without rebooting and this morning a thermal event forced a reboot and then I noticed. Of course, thanks to NixOS being super awesome, I could just boot previous generations and I found that the breakage happens sometime between 21.03pre246062.420f89ceb26 and nixos-21.03pre250162.34ad166a830.

The comparison is https://github.com/NixOS/nixpkgs/compare/420f89ceb26...34ad166a830 but GitHub crashes on that :frowning:

I don’t have time right now to investigate further, does this ring any bells for anyone?

I’ve been having a similar problem with an Apple Magic Trackpad on 20.09. The trackpad will pair, but then my computer won’t actually see any input from it.

Weirdly, my issue was fixed (at least temporarily) by rebooting into 20.03 and then back into 20.09. I only found this fix by accident and can’t even begin to explain it.

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I got it to work by unpairing and re-pairing. Hmm.

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The problem is that every time I reboot, I need to re-pair :disappointed:

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Workaround: https://wiki.archlinux.org/index.php/Bluetooth#Problems_with_all_BLE_devices_on_kernel_5.9+

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i’m very new to NixOS (loving it already), but i had trouble connecting my Apple Magic Trackpad using the Gnome settings app. it shows up briefly as a grayed out “tablet”, and then disappears.

maybe this will help someone, i managed to connect it using:

$ bluetoothctl
agent on
scan on    # then press the button on it, pick its address
pair 00:11:22:33...
trust 00:11:22:33...
connect 00:11:22:33...
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How well is the magic trackpad support under Linux?

Mine works … most of the time.

:sweat_smile:

I suppose you use libinput, and it can detect all gestures?

I do use libinput.

The only gestures I use are two-finger-up and two-finger-down. They both work. I’d be happy to test some others if you can tell me how (preferably under the pantheon window manager).

In a root shell, you can run nix-shell -p libinput --run 'libinput debug-events'.

I used sudo but then I couldn’t kill it :slight_smile:

it works ok, but it often disconnects for me when i touch (or two finger scroll?) near its edges.

After running that, I see debugging information for lots of gestures, including ones that I don’t normally use. I guess that’s good.

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