Bluetooth randomly cutting out in Ubuntu

18.04 bluetooth

Update Your Kernel

linux-image-generic version 4.15.0-46.49 and newer contain the fix. Changelog excerpt:

  * Bionic update: upstream stable patchset 2019-01-17 (LP: #1812229)
    - xhci: Fix perceived dead host due to runtime suspend race with event handler

The linux-image-generic fix was made available for these Ubuntu releases:

  • 18.10 (cosmic) – 28 October 2018 – version 4.17.0-7.8 and newer
  • 18.04 (bionic) – 15 February 2019 – version 4.15.0-46.49 and newer
  • 16.04 (xenial) – 27 September 2018 – version 4.4.0-136.162 and newer

To see what version of linux-image-generic you have and what versions are available to you, run these commands:

sudo apt update
apt-cache policy linux-image-generic

If you have a candidate with the fix to which you can update, just run an upgrade like so:

sudo apt full-upgrade

Install the linux-oem Kernel

Alternatively, you can try switching to the linux-oem kernel, which received the fix months earlier than the linux-image-generic branch did:

sudo apt install -y linux-oem

On 20 July 2018, linux-oem version 4.15.0-1012.15 was published to the bionic-security and bionic-updates repo. It included these changes from version 4.15.0-1010.13:

  * xhci hangs; reset results in NULL pointer dereference (LP: #1763594)
    - xhci: Create new structures to store xhci port information
    - xhci: set hcd pointers for xhci usb2 and usb3 roothub structures
    - xhci: Add helper to get xhci roothub from hcd
    - xhci: xhci-hub: use new port structures to get port address instead of port
      array
    - xhci: xhci-hub: use new port structures for cas and wake mask functions.
    - xhci: xhci-ring: use port structures for port event handler
    - xhci: rename faked_port_index to hcd_portnum
    - xhci: change xhci_set_link_state() to work with port structures
    - xhci: change xhci_test_and_clear_bit() to use new port structure
    - xhci: use port structures instead of port arrays in xhci.c functions
    - xhci: xhci-hub: use port structure members instead of xhci_get_ports()
    - xhci-mtk: use xhci hub structures to get number of ports in roothubs
    - xhci: xhci-mem: remove port_arrays and the code initializing them
    - xhci: debugfs: add usb ports to xhci debugfs
    - xhci: debugfs: add debugfs interface to enable compliance mode for a port
    - xhci: Fix perceived dead host due to runtime suspend race with event handler

The last patch in that list should fix the problem of Bluetooth randomly cutting out (as well as the camera and fingerprint scanner, if you have those).

The xHCI bugfix hasn't been applied to the main kernel yet at the time of writing, so linux-oem is the only packaged Ubuntu kernel release that has the fix.

For tracking information on this bug, see the "Resources" section at the bottom of this answer.

Hack: Restore Bluetooth without Rebooting

If you would rather wait for a fix to be backported to the generic Ubuntu kernel, you can run this hack whenever Bluetooth cuts out.

Your laptop's camera, fingerprint reader, and Bluetooth controller will quickly reconnect after running this command (both lines):

echo 1 | sudo tee /sys/bus/pci/devices/0000:00:14.0/remove &&
echo 1 | sudo tee /sys/bus/pci/rescan

Note: Make sure that 0000:00:14.0 is actually the xHCI controller before running the first command. You can find the slot with this command: lspci -k | grep -B2 xhci

Explanation

This is a Band-Aid and does not fix the root cause. For bug tracking and external discussion, see the "Resources" section at the bottom of this answer.

Here's how the bug runs:

Problem Start

A bug in the xhci_hcd driver convinces it that the xHCI host controller stopped responding. As a result, it disconnects all the devices connected to the controller:

Jul 25 09:07:31 host kernel: [121258.765591] xhci_hcd 0000:00:14.0: xHC is not running.
Jul 25 09:07:31 host kernel: [121258.772300] xhci_hcd 0000:00:14.0: xHCI host controller not responding, assume dead
Jul 25 09:07:31 host kernel: [121258.772319] xhci_hcd 0000:00:14.0: HC died; cleaning up
Jul 25 09:07:31 host kernel: [121258.806828] usb 1-7: USB disconnect, device number 2
Jul 25 09:07:31 host kernel: [121258.807915] usb 1-8: USB disconnect, device number 3
Jul 25 09:07:31 host kernel: [121258.808717] usb 1-12: USB disconnect, device number 5
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.1
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-8
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-7
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-12/1-12:1.0/bluetooth/hci0/hci0:256/0005:0A5C:4503.001E
Jul 25 09:07:31 host systemd[1]: bluetooth.target: Unit not needed anymore. Stopping.
Jul 25 09:07:31 host systemd[1]: Stopped target Bluetooth.
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-12/1-12:1.1
Jul 25 09:07:31 host bluetoothd[12402]: Endpoint unregistered: sender=:1.61 path=/MediaEndpoint/A2DPSource
Jul 25 09:07:31 host bluetoothd[12402]: Endpoint unregistered: sender=:1.61 path=/MediaEndpoint/A2DPSink
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-12/1-12:1.0
Jul 25 09:07:31 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-12
Jul 25 09:07:31 host NetworkManager[4095]: <info>  [1532527651.6587] bluez5: NAP: removed interface 28:16:AD:2B:5C:40

(From /var/log/syslog)

Removal of xHCI Controller

Running echo 1 | sudo tee /sys/bus/pci/devices/0000:00:14.0/remove hot-removes the xHCI controller PCI device:

Jul 25 09:09:57 host kernel: [121405.007193] xhci_hcd 0000:00:14.0: remove, state 4
Jul 25 09:09:57 host kernel: [121405.007208] usb usb2: USB disconnect, device number 1
Jul 25 09:09:57 host kernel: [121405.008109] xhci_hcd 0000:00:14.0: USB bus 2 deregistered
Jul 25 09:09:57 host kernel: [121405.008215] xhci_hcd 0000:00:14.0: remove, state 4
Jul 25 09:09:57 host kernel: [121405.008226] usb usb1: USB disconnect, device number 1
Jul 25 09:09:57 host kernel: [121405.010736] xhci_hcd 0000:00:14.0: USB bus 1 deregistered
Jul 25 09:09:57 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-0:1.0
Jul 25 09:09:57 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-0:1.0
Jul 25 09:09:57 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb2
Jul 25 09:09:57 host upowerd[6035]: unhandled action 'unbind' on /sys/devices/pci0000:00/0000:00:14.0/usb1

(From /var/log/syslog)

Restoring the xHCI Controller

Running echo 1 | sudo tee /sys/bus/pci/rescan rediscovers the PCI device we just removed. The xhci_hcd driver sees the rediscovered PCI device as a new USB bus and sets up the bus and its devices:

Jul 25 09:10:11 host kernel: [121418.409659] pci 0000:00:14.0: [8086:a12f] type 00 class 0x0c0330
Jul 25 09:10:11 host kernel: [121418.409686] pci 0000:00:14.0: reg 0x10: [mem 0x3e820000-0x3e82ffff 64bit]
Jul 25 09:10:11 host kernel: [121418.409773] pci 0000:00:14.0: PME# supported from D3hot D3cold
Jul 25 09:10:11 host kernel: [121418.428182] pci 0000:00:14.0: BAR 0: assigned [mem 0x3e820000-0x3e82ffff 64bit]
Jul 25 09:10:11 host kernel: [121418.428928] xhci_hcd 0000:00:14.0: xHCI Host Controller
Jul 25 09:10:11 host kernel: [121418.428936] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 1
Jul 25 09:10:11 host kernel: [121418.430031] xhci_hcd 0000:00:14.0: hcc params 0x200077c1 hci version 0x100 quirks 0x00109810
Jul 25 09:10:11 host kernel: [121418.430037] xhci_hcd 0000:00:14.0: cache line size of 128 is not supported
Jul 25 09:10:11 host kernel: [121418.430401] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
Jul 25 09:10:11 host kernel: [121418.430404] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
Jul 25 09:10:11 host kernel: [121418.430407] usb usb1: Product: xHCI Host Controller
Jul 25 09:10:11 host kernel: [121418.430410] usb usb1: Manufacturer: Linux 4.15.0-29-generic xhci-hcd
Jul 25 09:10:11 host kernel: [121418.430412] usb usb1: SerialNumber: 0000:00:14.0
Jul 25 09:10:11 host kernel: [121418.430671] hub 1-0:1.0: USB hub found
Jul 25 09:10:11 host kernel: [121418.430725] hub 1-0:1.0: 16 ports detected
Jul 25 09:10:11 host kernel: [121418.432783] xhci_hcd 0000:00:14.0: xHCI Host Controller
Jul 25 09:10:11 host kernel: [121418.432792] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 2
Jul 25 09:10:11 host kernel: [121418.433063] usb usb2: New USB device found, idVendor=1d6b, idProduct=0003
Jul 25 09:10:11 host kernel: [121418.433067] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
Jul 25 09:10:11 host kernel: [121418.433070] usb usb2: Product: xHCI Host Controller
Jul 25 09:10:11 host kernel: [121418.433076] usb usb2: Manufacturer: Linux 4.15.0-29-generic xhci-hcd
Jul 25 09:10:11 host kernel: [121418.433078] usb usb2: SerialNumber: 0000:00:14.0
Jul 25 09:10:11 host kernel: [121418.436200] hub 2-0:1.0: USB hub found
Jul 25 09:10:11 host kernel: [121418.436223] hub 2-0:1.0: 10 ports detected
Jul 25 09:10:11 host kernel: [121418.771883] usb 1-7: new high-speed USB device number 2 using xhci_hcd
Jul 25 09:10:11 host kernel: [121418.949715] usb 1-7: New USB device found, idVendor=04ca, idProduct=7053
Jul 25 09:10:11 host kernel: [121418.949721] usb 1-7: New USB device strings: Mfr=3, Product=1, SerialNumber=2
Jul 25 09:10:11 host kernel: [121418.949725] usb 1-7: Product: HP HD Camera
Jul 25 09:10:11 host kernel: [121418.949729] usb 1-7: Manufacturer: DETNQ019I53FY0
Jul 25 09:10:11 host kernel: [121418.949732] usb 1-7: SerialNumber: 200901010001
Jul 25 09:10:11 host kernel: [121418.958393] uvcvideo: Found UVC 1.00 device HP HD Camera (04ca:7053)
Jul 25 09:10:11 host kernel: [121418.961311] uvcvideo 1-7:1.0: Entity type for entity Extension 4 was not initialized!
Jul 25 09:10:11 host kernel: [121418.961319] uvcvideo 1-7:1.0: Entity type for entity Processing 2 was not initialized!
Jul 25 09:10:11 host kernel: [121418.961324] uvcvideo 1-7:1.0: Entity type for entity Camera 1 was not initialized!
Jul 25 09:10:11 host kernel: [121418.962085] input: HP HD Camera: HP HD Camera as /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/input/input59
Jul 25 09:10:11 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-0:1.0
Jul 25 09:10:11 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2
Jul 25 09:10:11 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-0:1.0
Jul 25 09:10:11 host kernel: [121419.091967] usb 1-8: new full-speed USB device number 3 using xhci_hcd
Jul 25 09:10:11 host kernel: [121419.241717] usb 1-8: New USB device found, idVendor=138a, idProduct=003f
Jul 25 09:10:11 host kernel: [121419.241723] usb 1-8: New USB device strings: Mfr=0, Product=0, SerialNumber=1
Jul 25 09:10:11 host kernel: [121419.241727] usb 1-8: SerialNumber: 00b080f6fa9d
Jul 25 09:10:12 host kernel: [121419.371938] usb 1-12: new full-speed USB device number 4 using xhci_hcd
Jul 25 09:10:12 host kernel: [121419.529258] usb 1-12: New USB device found, idVendor=8087, idProduct=0a2b
Jul 25 09:10:12 host kernel: [121419.529263] usb 1-12: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1
Jul 25 09:10:12 host kernel: [121419.537804] Bluetooth: hci0: Firmware revision 0.0 build 176 week 45 2017
Jul 25 09:10:12 host mtp-probe: checking bus 1, device 2: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-7"
Jul 25 09:10:12 host mtp-probe: checking bus 1, device 3: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-8"
Jul 25 09:10:12 host mtp-probe: bus: 1, device: 2 was not an MTP device
Jul 25 09:10:12 host mtp-probe: bus: 1, device: 3 was not an MTP device
Jul 25 09:10:12 host kernel: [121419.589011] Bluetooth: hci0: Hardware error 0x0c
Jul 25 09:10:12 host NetworkManager[4095]: <info>  [1532527812.3141] bluez5: NAP: added interface 28:16:AD:2B:5C:40
Jul 25 09:10:12 host kernel: [121419.598737] Bluetooth: hci0: last event is not cmd complete (0x0f)
Jul 25 09:10:12 host kernel: [121419.598745] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
Jul 25 09:10:12 host bluetoothd[12402]: Endpoint registered: sender=:1.61 path=/MediaEndpoint/A2DPSource
Jul 25 09:10:12 host bluetoothd[12402]: Endpoint registered: sender=:1.61 path=/MediaEndpoint/A2DPSink
Jul 25 09:10:12 host systemd[1]: Reached target Bluetooth.
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-8
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.1
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-12/1-12:1.1
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-12/1-12:1.0
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-12
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0
Jul 25 09:10:12 host upowerd[6035]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb1/1-7

(From /var/log/syslog)

As a result, the xhci_hcd driver rediscovers the attached camera, fingerprint reader, and Bluetooth controller.

Resources

  • Kernel upstream
    status-completed— Fix released
    Kernel 4.17.10 changelog
  • Ubuntu bug report
    status-completed― Fix released
    xhci hangs; reset results in NULL pointer dereference
  • Debian bug report
    status-stale― Last updated 2016-08-25
    Keyboard/Mouse devices are disconnecting after some time or event (capslock, ) - unknown main item tag 0x0
  • Kernel bug report
    status-declined― Assignee said bug was off-topic
    Enabling USB (auto)suspend (power control) for xHCI controllers incurs random device failures since kernel 4.15
  • Arch Linux Forums discussion
    status-reproduced― Bug affects forum users
    xHCI host controller not responding, assume dead

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