Linux – How to improve weak Bluetooth signal on a Linux laptop

bluetoothlaptoplinux

I'm using Linux KDE Neon on a Dell laptop. There is a software issue that is causing the Bluetooth signal to be drastically weaker than it is supposed to be. I know that, because I used to be able to walk away (inside a single room, around seven meters) from my laptop with Bluetooth headphones without issues. Now, the same headphones can not connect when within 1.5 meters (5 feet) of the laptop. When connected, the sound cuts out when the distance increases above one meter (3 feet). These headphones are the only device connected to the laptop over Bluetooth.

  • Linux Laptop Issue: I know that this is an issue on the Linux laptop, because I tested the same headphones with other Bluetooth devices in the same room: a different PC with a Bluetooth dongle, a MacBook, and two different Android phones. All of them connect and work without audio cutting out in 5-7 meters range.
  • Weak Signal: I know that this is a weak signal issue, because the headphones connect to the laptop and work normally when I move them within 30 cm (one foot) of the laptop.
  • Software Issue: I know that this is a software issue, because recently after some combination of different invocations of bluetoothctl, rfkill, and sudo systemctl restart bluetooth.service the issue went away. Unfortunately, the issue came back when I rebooted the OS, and I haven't been able to reproduce this workaround since.
  • WiFi is turned off on this laptop.

In my usual physical setup, hcitool rssi ... returns values between -63 and -66. hcitool lq almost always returns 255. (from this answer on the Linux and Unix SE)

Is there any way in Linux to boost the Bluetooth signal strength from software without additional hardware?

Could this be a bug in my configuration? Could this be a bug in BlueZ? Linux kernel?

Also, after observing this for some time, it seems that there is another symptom. Bluetooth signal is fine when the audio is continuous. That is, if I'm far enough from the laptop, then as soon as a song or video end, the Bluetooth headphones are disconnected. Can Pulseaudio affect Bluetooth connections like that?

Best Answer

The solution to my problem is: open the laptop lid. I'm using external monitor, keyboard, and mouse. The laptop lid is almost always closed. However, when the lid is opened, there are no Bluetooth issues which were described in the question.

I guess that when I got Bluetooth to work:

  • Software Issue: I know that this is a software issue, because recently after some combination of different invocations of bluetoothctl, rfkill, and sudo systemctl restart bluetooth.service the issue went away. Unfortunately, the issue came back when I rebooted the OS, and I haven't been able to reproduce this workaround since.

the laptop was opened just by accident.

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