Traceback when unplugging USB port replicator

[Jamie Strandboge]

I have a lenovo USB 2.0 port replicator with Digtial Video (MODEL #VDK8736). I discovered that whenever I unplugged my port replicator, there would be a kernel traceback. My laptop has a VGA port which I plug an external monitor into, and I use the port replicator for network, keyboard, mouse, and sound (ie, I don't use the digital video on the port replicator). This configuration works fine until I unplug the port replicator and I get a traceback (see attached logs). The system is mostly usable in this state, though it can cause problems later with suspend/resume/unlock where the screensaver sometimes can't receive input. I can still trigger the traceback if I only use the port replicator without using an external monitor.

Booting into the linux-image-3.12.0-2-generic (3.12.0-2.7), I don't get a traceback when unplugging the port replicator.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-18-generic 3.13.0-18.38
ProcVersionSignature: Ubuntu 3.13.0-18.38-generic 3.13.6
Uname: Linux 3.13.0-18-generic x86_64
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jamie 2869 F.... pulseaudio
CurrentDesktop: Unity
Date: Fri Mar 21 07:03:38 2014
HibernationDevice: RESUME=UUID=c4c5dbc0-d41a-428d-8af4-b680b67dd3dc
InstallationDate: Installed on 2011-06-28 (996 days ago)
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110425.2)
Lsusb:
 Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 5129CTO
ProcFB:
 0 inteldrmfb
 1 udldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-18-generic root=UUID=88689ad2-74b5-442c-9290-8ae60b63e16b ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-18-generic N/A
 linux-backports-modules-3.13.0-18-generic N/A
 linux-firmware 1.126
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
UpgradeStatus: Upgraded to trusty on 2013-11-04 (136 days ago)
dmi.bios.date: 02/24/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 6QET64WW (1.34 )
dmi.board.name: 5129CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr6QET64WW(1.34):bd02/24/2011:svnLENOVO:pn5129CTO:pvrThinkPadX201s:rvnLENOVO:rn5129CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 5129CTO
dmi.product.version: ThinkPad X201s
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[Jamie Strandboge (jdstrand)]

This was all prompted by me thinking there was a bug in lightdm/screenlocking since I was sometimes unable to suspend/resume/unlock. I'm going to attach my test matrix procedure for how I discovered the traceback and proved to myself that the traceback is the most likely cause of my failure to unlock after suspend/resume. I don't think this is needed for testing the kernel bug, but I will likely run through it once there is a fix.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.14 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14-rc7-trusty/

[Jamie Strandboge (jdstrand)]

Using the amd64 kernel in http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14-rc7-trusty/, I can reproduce the problem. Attached is the dmesg after booting with the port replicator plugged in and unplugging.

[Jamie Strandboge (jdstrand)]

Oh, I forgot to add the tag, kernel-bug-exists-upstream. Adding now.

[Jamie Strandboge (jdstrand)]

Moving back to 'Incomplete' in case the bot depends on that.

[Jamie Strandboge (jdstrand)]

This bug no longer seems to affect new kernels. Marking Fix Released for now. I'll file a new bug if it comes up again.