Unknown "Video Bus" device continuously generates keys combination

[Leonid Kuzmin]

Issue starts at boot process and looks like repetitive generation "^@" symbol combination in console. In the graphical interface it causes windows and cursor flickering, but only after login screen (login screen is working well) and when switching to console (ctrl + alt + f1) I'm not able to login because all keyboard input is mixed with "^@" symbols. Experimentally I found that issue is caused by unknown device listed as "Video Bus" in xinput --list:
$xinput --list --long
↳ Video Bus id=8 [slave keyboard (3)]
 This device is disabled
 Reporting 1 classes:
  Class originated from: 8. Type: XIKeyClass
  Keycodes supported: 248

When device is disabled by following command:
$xinput set-prop 8 "Device Enabled" 0

Flickering of graphics stops, and after switching to console (ctrl + alt + f1) and back (ctrl + alt + f7) the device is enabled back.
If second monitor is plugged flickering of windows stops and system starts to turn off and on both monitors with different resolutions.

Here are all possible details of the "Video Bus" device which I managed to found:
$xinput --watch-props 8
Device 'Video Bus':
 Device Enabled (140): 0
 Coordinate Transformation Matrix (142): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
 Device Product ID (257): 0, 6
 Device Node (258): "/dev/input/event7"
 Virtual Device (259): 1

$cat /proc/bus/input/devices
I: Bus=0019 Vendor=0000 Product=0006 Version=0000
N: Name="Video Bus"
P: Phys=LNXVIDEO/video/input0
S: Sysfs=/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:19/LNXVIDEO:00/input/input7
U: Uniq=
H: Handlers=kbd event7
B: PROP=0
B: EV=3
B: KEY=3e000b 0 0 0 0 0 0 0

$lsinput -v
/dev/input/event7
   bustype : BUS_HOST
   vendor : 0x0
   product : 0x6
   version : 0
   name : "Video Bus"
   phys : "LNXVIDEO/video/input0"
   bits ev : EV_SYN EV_KEY

I'm sure that it is not defective hardware-caused issue because: 1) Laptop has been diagnosed in service center, 2) There is no issues in MS Windows

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-31-generic-pae 3.2.0-31.50
ProcVersionSignature: Ubuntu 3.2.0-31.50-generic-pae 3.2.28
Uname: Linux 3.2.0-31-generic-pae i686
NonfreeKernelModules: fglrx
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu13
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: PCH [HDA Intel PCH], device 0: STAC92xx Analog [STAC92xx Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: zuker 2378 F.... pulseaudio
CRDA:
 country AU:
  (2402 - 2482 @ 40), (N/A, 20)
  (5170 - 5250 @ 40), (3, 23)
  (5250 - 5330 @ 40), (3, 23), DFS
  (5735 - 5835 @ 40), (3, 30)
Card0.Amixer.info:
 Card hw:0 'PCH'/'HDA Intel PCH at 0xf7c00000 irq 51'
   Mixer name : 'Intel CougarPoint HDMI'
   Components : 'HDA:111d76d1,102804b3,00100205 HDA:80862805,80860101,00100000'
   Controls : 23
   Simple ctrls : 11
Date: Mon Oct 8 12:20:51 2012
HibernationDevice: RESUME=UUID=1b4ff2b2-b40f-4b46-8a5c-29172cb6e299
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
MachineType: Dell Inc. Vostro 3550
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-31-generic-pae root=UUID=88fd96e5-1fee-4a86-badb-87fe4d32cb0c ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-31-generic-pae N/A
 linux-backports-modules-3.2.0-31-generic-pae N/A
 linux-firmware 1.79.1
SourcePackage: linux
StagingDrivers: mei
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/30/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A09
dmi.board.name: 0PD77K
dmi.board.vendor: Dell Inc.
dmi.board.version: A09
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: Not Specified
dmi.modalias: dmi:bvnDellInc.:bvrA09:bd09/30/2011:svnDellInc.:pnVostro3550:pvrNotSpecified:rvnDellInc.:rn0PD77K:rvrA09:cvnDellInc.:ct8:cvrNotSpecified:
dmi.product.name: Vostro 3550
dmi.product.version: Not Specified
dmi.sys.vendor: Dell Inc.

[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 v3.6 kernel[0] (Not a kernel in the daily directory) and install both the linux-image and linux-image-extra .deb packages.

Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. Please only remove that one tag and leave the other tags. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text.

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/v3.6-quantal/

[Leonid Kuzmin (zuker)]

Tested in mainline kernel, bug fixed, appropriate tag added.
What I'm supposed to do now for workaround? Use mainline kernel?

[Leonid Kuzmin (zuker)]

Shame on me! I've not installed extras and headers packages for mainline kernel, with all these packages bug is still present, so changing tags.

[Leonid Kuzmin (zuker)]

It looks like issue with GUI blinking is fixed but continuous generation of keypress event which looks like "^@" in TTY remains.

[penalvch (penalvch)]

zuker, as per http://www.dell.com/support/troubleshooting/us/en/19/Product/vostro-3550 an update is available for your BIOS (A11). If you update to this, does it change anything?

If not, could you please both specify what happened, and provide the output of the following terminal command:
sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date

Thank you for your understanding.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Leonid Kuzmin (zuker)]

Christopher, thanks for suggestion! I'v updated BIOS:
$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
A11
08/03/2012
But "^@" sequence generation remains. Also I've noticed that the mentioned sequence generated on power adapter plug/unplug.

[Leonid Kuzmin (zuker)]

Just cleanly installed Saucy, issue remains.

[penalvch (penalvch)]

zuker, could you please test the latest mainline kernel via http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.12-rc5-saucy/ and advise on if this is reproducible?

[Leonid Kuzmin (zuker)]

Christopher, I've installed the latest mainline kernel, but it has no effect, "^@" sequence remains. Thanks for help anyway!

[penalvch (penalvch)]

Leonid Kuzmin, did this problem not occur in a release prior to Precise?

[Leonid Kuzmin (zuker)]

Christopher, I've also spotted this bug on Oneiric live cd.

[penalvch (penalvch)]

Leonid Kuzmin, for regression testing purposes, could you please test for this in Lucid via http://old-releases.ubuntu.com/releases/lucid/ and advise to the results?

[Leonid Kuzmin (zuker)]

Christopher, is testing on LiveCD is acceptable?

[penalvch (penalvch)]

Leonid Kuzmin, if the problem was reproducible in a Live environment before, testing this would be fine.

[Rajib Lochan Dhibar (rajibldr)]

My Test Results
=============
This bug don't create problem in KDE (tested with Kubuntu 12.04 (32 + 64bit); Debian-live-7.0.0-i386-kde-desktop; Linux Mint 13 Maya-KDE-32bit) based distros. So, this bug isn't bug there.

I also tested with recent GNOME based distros (Ubuntu 12.04 (32 + 64bit), Debian 7.1.0-i386-GNOME, Kali Linux 1.0.3-i386-GNOME), problem exists.

But in pre-installed Dell Ubuntu 10.10 (Dell Ubuntu 10.10 Reinstallation Media.iso) this bug don't occur. After update to 11.04 this bug comes. Also in Ubuntu-10.04.4 this isn't bug.

I Guess (not confirmed)
===================
Video Bus id=8 [slave keyboard (3) is the input device fingerprint-reader/scanner of the laptop!
https://bugs.launchpad.net/ubuntu/+source/libfprint/+bug/790183

Right now I can't go further, have other important work, so exiting.

[Leonid Kuzmin (zuker)]

Rajib, thanks for help! It seems "Video Bus" isn't a fingerprint reader:
$ lsusb | grep Finger
Bus 002 Device 004: ID 138a:0011 Validity Sensors, Inc. VFS5011 Fingerprint Reader

[penalvch (penalvch)]

Rajib Lochan Dhibar, if you have a bug in Ubuntu, the Ubuntu Kernel team, Ubuntu Bug Control team, and Ubuntu Bug Squad would like you to please file a new report by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Please note, not filing a new report would delay your problem being addressed as quickly as possible.

No need exists to comment here at this time. After reading the above documentation in it's entirety, if you have further questions, you are welcome to redirect them to the appropriate mailing list or forum via http://www.ubuntu.com/support/community/mailinglists , or you may contact me directly.

Thank you for your understanding.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Mattheus Erb (mattheus-erb)]

This "^@" - Problem still exist. (Linux 4.7.6)
But it seems to be solved when i turn off modesetting for the radeon module.

[penalvch (penalvch)]

Mattheus Erb, it will help immensely if you filed a new report with the Ubuntu repository kernel (not mainline/upstream) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.