kernel panic connecting display port to Dell Latitude E7470

[Anton Piatek]

Connecting an external Display Port screen wither via the dell E-Port plus or directly via the miniDP causes a kernel panic. The crash is not always immediate, if the internal screen is disabled when docked, then the external screen may work, though undocking and docking a second time usually crashes it.

Kernels crashing for me are 4.4.0-21-generic and 4.4.0-22-generic.

Testing with the mainline kernel linux-image-4.4.12-040412-generic=4.4.12-040412.201606011712 has not yet caused the panic

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-22-generic 4.4.0-22.40
ProcVersionSignature: Ubuntu 4.4.0-22.40-generic 4.4.8
Uname: Linux 4.4.0-22-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: anton 1885 F.... pulseaudio
CurrentDesktop: Unity
Date: Mon Jun 6 08:25:23 2016
InstallationDate: Installed on 2016-06-01 (4 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 004: ID 8087:0a2b Intel Corp.
 Bus 001 Device 003: ID 0a5c:5800 Broadcom Corp. BCM5880 Secure Applications Processor
 Bus 001 Device 002: ID 1bcf:28b8 Sunplus Innovation Technology Inc.
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Dell Inc. Latitude E7470
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-22-generic root=UUID=7bebd315-73de-4106-9fef-07139edd58f2 ro rootflags=subvol=@ quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-22-generic N/A
 linux-backports-modules-4.4.0-22-generic N/A
 linux-firmware 1.157
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/18/2016
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.5.3
dmi.board.name: 0T6HHJ
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.5.3:bd04/18/2016:svnDellInc.:pnLatitudeE7470:pvr:rvnDellInc.:rn0T6HHJ:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E7470
dmi.sys.vendor: Dell Inc.

[Anton Piatek (anton-piatek)]

Possibly related to +1560524

[Brad Figg (brad-figg)]

This change was made by a bot.

[Anton Piatek (anton-piatek)]

Looks like it is not working today with any of the above kernels - I had multiple screens working ok on Friday with the mainline kernel, but today it is not working. I'm not sure what changed, I will attach the dpkg log, but am going to have to go to windows as this is a work laptop and i can't spend more time looking at this. Hopefully I can help debug in future if I get time to repartition again or perhaps with a beta live-usb image

[Joseph Salisbury (jsalisbury)]

The issue even started happening on the mainline kernel? If so, maybe try the latest mainline kernel:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.7-rc1-yakkety/