Bluetooth issue RTL8761b

Ive been using manjaro for about 6 months on my laptop, as it has works great, and I decided to make the jump on my desktop as well. On my laptop I had Bluetooth trouble, I managed to fix most of it (there is still one problem, but it is predictable as it happens only once a day, after I connect the device). Now, on my desktop, I’m facing bluetooth issues as well. I bought a bluetooth adaptor to use my mouse (logitech mx master 2s) on the desktop.

after downloading this aur package regarding the RTL8761b firmware, the mouse paired and connected with no problem. I didn’t have one of the problems I had with it on the laptop. But There is a weird problem nonetheless. It stops working for a few seconds every few minutes.

Its not when the computer sleeps. its not when I don’t use it for a while. It seems completely random. I haven’t managed to time it precisely, but i suspect it happens at some fixed interval of time. it Doesn’t seems like I lose the bluetooth connection either. but I’m not 100% sure how to test this.

I’m not sure how relevant it is, but I’m on kernel 5.8.18-1

Does someone has any idea of what could be happening?

edit: I don’t think its a problem with the adapter, because it works fine on windows, and even on Linux, my bluetooth headphones have a continuous sound output, even when the mouse freezes. So it looks like it is a mouse problem? Also, the time between the last two freezes has been about 240 seconds. I’ve no idea if it is relevant.

edit2: i still haven’t fixed it. The freezes defintely arent happening on a fixed time interval. ALtough yesterday it felt it was, now sometimes it works for hours, and sometimes stops after a few minutes. Writing this edit it stopped twice. But something that might help, when i’ve got bluetoothctl open on the konsole, every time the mouse stops working, the following appears

Agent registered
[CHG] Device D1:0B:4A:BC:D3:8D ServicesResolved: no
[CHG] Device D1:0B:4A:BC:D3:8D Connected: no
[CHG] Device D1:0B:4A:BC:D3:8D Connected: yes
[CHG] Device D1:0B:4A:BC:D3:8D ServicesResolved: yes

Update. I still haven’t solved it, but on journalctl when the mouse disconnects, the following happens

nov 29 18:56:09 paulo-pc org_kde_powerdevil[1639]: QObject::disconnect: Unexpected nullptr parameter
nov 29 18:56:09 paulo-pc org_kde_powerdevil[1639]: QObject::disconnect: Unexpected nullptr parameter
nov 29 18:56:12 paulo-pc kernel: input: MX Master 2S Keyboard as /devices/virtual/misc/uhid/0005:046D:B019.0013/input/input66
nov 29 18:56:12 paulo-pc kernel: input: MX Master 2S Mouse as /devices/virtual/misc/uhid/0005:046D:B019.0013/input/input67
nov 29 18:56:12 paulo-pc kernel: hid-generic 0005:046D:B019.0013: input,hidraw2: BLUETOOTH HID v0.06 Keyboard [MX Master 2S] on 00:e0:4c:71:33:03
nov 29 18:56:12 paulo-pc systemd-logind[563]: Watching system buttons on /dev/input/event4 (MX Master 2S Keyboard)
nov 29 18:56:13 paulo-pc kcminit[30852]: Initializing “kcm_mouse” : “kcminit_mouse”
nov 29 18:56:13 paulo-pc kwin_x11[1070]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 35716, resource id: 90177541, major code: 18 (ChangeProperty), minor code: 0

I’m a bit curious on why it considers the mouse a keyboard as well.
Does that help in anyway to identify the problem?

I also have the same problem. Both with Logitech’s proprietary protocol using their dongle, and also with bluetooth. Archwiki has a full page dedicated to the Master mouse series, but it mentions only laggyness with bluetooth. I’ve followed the suggestions in Bluetooth - ArchWiki, which helped a little, but has not solved the issue.

I’ve noticed that the mouse lags constantly under heavy CPU load. It indicates some priority issues: even though the recognition of a mouse movement is can not be CPU intensive, and I thought these are handled with some kind of interrupt, or at least with high priority in the OS, it is clear that once the processor is busy the mouse is useless.

I am sure, that the mouse is OK, since in other machines it works fine.

PS: The bluetooth dongle works just fine with my bluetooth headphone, without any hickups.