Bluetooth lock up on Raspberry Pi 3B+

[Bing Xiao]

Same issue already been reported at https://github.com/raspberrypi/firmware/issues/887. The contributor of raspberrypi/firmware @pelwell submitted a patch of UART driver which should fix the problem. Will Ubuntu mate include the patches from raspberrypi/linux branches? And when?

Below is the my bug description, more details can be found on above github link:

Bluetooth connection will lost after several minutes audio playback, and the program will lockup when try to stop the stream.
The log of dmesg:
Bluetooth: hci1: hardware error 0x00
Bluetooth: hci1: command 0x1003 tx timeout
Bluetooth: hci1: command 0x1001 tx timeout
Bluetooth: hci1: command 0x1009 tx timeout

The log of bluealsa:
bluealsa: D: ../../src/ba-transport.c:1020: Releasing transport: A2DP Source (SBC)
bluealsa: E: Couldn't release transport: GDBus.Error:org.freedesktop.DBus.Error.UnknownObject: Method "Release" with signature "" on interface "org.bluez.MediaTransport1" doesn't exist
bluealsa: D: ../../src/ba-transport.c:1200: Exiting IO thread: A2DP Source (SBC)
bluealsa: D: ../../src/ba-transport.c:1020: Releasing transport: A2DP Source (SBC)
bluealsa: E: Couldn't release transport: GDBus.Error:org.freedesktop.DBus.Error.UnknownObject: Method "Release" with signature "" on interface "org.bluez.MediaTransport1" doesn't exist

I was using bluez-alsa on a Raspberry Pi 3B+ running latest Ubuntu-mate, 18.04.4 LTS (GNU/Linux 4.15.0-1054-raspi2 armv7l). The Bluez version is 5.48 from the depot originally. I have tried to upgrade Bluez to 5.52, but can not fix the problem.

When the issue happens, bluetooth will go off and stop responding completely. And I can not turn on bluetooth anymore, below is the output of bluetoothctl:
[bluetooth]# power on
Failed to set power on: org.bluez.Error.Failed
Restarting bluetooth service or bluealsa will also not help, the only way to recover is a reboot.

[Bing Xiao (bing.xiao)]

I have tried to build and install the latest rpi-4.19.y branch of https://github.com/raspberrypi/linux on My 3B+ running Ubuntu-Mate 18.04. And confirm that it fixed the Bluetooth problem. I leave it play audio overnight and cannot see an disconnection.
The path is https://github.com/raspberrypi/linux/commit/65aa6ec0faaa012508489886ac357cbb86cdb9a4

[Launchpad Janitor (janitor)]

[Expired for Ubuntu MATE because there has been no activity for 60 days.]