[Bug 1176680] [NEW] Bluetooth dangerously unstable on Dell Q15R (N5110)

Cefn launchpad.net at cefn.com
Sun May 5 22:37:21 UTC 2013

Public bug reported:

Some kind of major kernel issue has been triggered on three separate
occasions in the last couple of days when trying to manipulate a
bluetooth serial rfcomm socket. This issue has persisted through a
kernel update (yesterday) and I just experienced it again a few moments

The symptoms are that the desktop drops to scrolling black text, and
CTRL+ALT+F1 is unresponsive, leaving the only option a hard shutdown.
The entire desktop session is lost.

This has been triggered simply by trying to connect/disconnect a
Bluetooth serial device (known as a JY-MCU). The tools I've been using
to send and receive data over the /dev/rfcomm0 device are python-serial
and Arduino. You can see the tools and commands I've been using to pair
and connect the device at

In the case of python-serial, the operation of the program is only possible after _binding_, as it seems to want to connect the port itself...
rfcomm bind rfcomm ${MACADDRESS}

...whilefor Arduino, the following is needed, as it needs a _connected_ port
rfcomm connect rfcomm0 ${MACADDRESS}

They certainly don't play nicely together. Java/Arduino seems to be
mismanaging the serial device - it doesn't release it when not in use,
so I have to shut down Arduino completely to then launch python. In
principle this is something I can cope with as I don't need both at the
same time.

However, hitting total kernel panic is not acceptable and means my
project work on Bluetooth may be impossible to progress.

I'm currently running the hcidump log and I suppose I may be able to
gather something from the next time it occurs. Not sure what else I can
report about the global brownout which is experienced by the 13.04
desktop, since I have no console access at all once the bug appears.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: bluetooth (not installed)
ProcVersionSignature: Ubuntu 3.8.0-19.30-generic 3.8.8
Uname: Linux 3.8.0-19-generic i686
ApportVersion: 2.9.2-0ubuntu8
Architecture: i386
Date: Sun May  5 23:22:55 2013
InterestingModules: bnep rfcomm btusb bluetooth
MachineType: Dell Inc. Inspiron N5110
MarkForUpload: True
 PATH=(custom, no user)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-19-generic root=UUID=c9767810-263a-424a-80cd-714fd4a9afa1 ro quiet splash
SourcePackage: bluez
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/22/2012
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A10
dmi.board.name: 0HVRTT
dmi.board.vendor: Dell Inc.
dmi.board.version: A10
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: Not Specified
dmi.modalias: dmi:bvnDellInc.:bvrA10:bd03/22/2012:svnDellInc.:pnInspironN5110:pvrNotSpecified:rvnDellInc.:rn0HVRTT:rvrA10:cvnDellInc.:ct8:cvrNotSpecified:
dmi.product.name: Inspiron N5110
dmi.product.version: Not Specified
dmi.sys.vendor: Dell Inc.
 hci0:	Type: BR/EDR  Bus: USB
 	BD Address: BC:77:37:BB:22:03  ACL MTU: 310:10  SCO MTU: 64:8
 	RX bytes:976 acl:0 sco:0 events:43 errors:0
 	TX bytes:907 acl:0 sco:0 commands:42 errors:0

** Affects: bluez (Ubuntu)
     Importance: Undecided
         Status: New

** Tags: apport-bug i386 raring

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