Intel chipset driver bug on Ubuntu certified Dell Latitude E5420: connecting power cord makes kworker run amok

[Otto Kekäläinen]

I've noticed that sometimes when I'm running on battery and then insert the power cord, the system slows down significantly. When I remove the power cord, it runs fine again, and when I reattach the power cord the system slows down again.

I'm running the latest Ubuntu 12.04 with all updates on a pre-installed Dell Latitude E5420 that is supposed to work perfectly with Ubuntu, since it is officially certified.

While the sluggishness happens, running 'top' shows several kworker processes:
top - 21:29:24 up 14:01, 4 users, load average: 1.91, 2.16, 2.06
Tasks: 208 total, 3 running, 202 sleeping, 0 stopped, 3 zombie
Cpu(s): 5.6%us, 2.2%sy, 0.0%ni, 91.7%id, 0.5%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 1891244k total, 1782568k used, 108676k free, 22512k buffers
Swap: 2004988k total, 812400k used, 1192588k free, 550600k cached

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
16561 otto 20 0 526m 15m 7796 S 14 0.9 1:10.79 gnome-system-mo
16534 root 20 0 0 0 0 R 7 0.0 0:16.66 kworker/1:2
 1215 root 20 0 275m 25m 4472 S 6 1.4 11:31.39 Xorg
16362 root 20 0 0 0 0 S 3 0.0 0:10.00 kworker/0:1
 1889 otto 20 0 1470m 64m 12m S 3 3.5 10:07.92 compiz
16287 root 20 0 0 0 0 S 3 0.0 0:13.85 kworker/3:2
 2306 otto 20 0 652m 14m 5056 S 2 0.8 0:31.76 gnome-terminal
17304 otto 20 0 17480 1384 964 R 1 0.1 0:00.03 top

Using commands
sudo perf record -ag sleep 30
sudo perf report
I was able to find out that the kworker threads running amok are due to the Intel I2C driver:
...
 2.91% kworker/1:2 [kernel.kallsyms] [k] na
                |
                --- native_read_tsc
                   |
                   |--62.97%-- delay_tsc
                   | |
                   | |--53.92%-- __udelay
                   | | |
                   | | |--50.48%-- sclhi
                   | | | |
                   | | | |--94.88%-- i2c_outb
...
 2.76% kworker/1:0 [kernel.kallsyms] [k] na
                |
                --- native_read_tsc
                   |
                   |--69.42%-- delay_tsc
                   | |
                   | |--58.89%-- __udelay
                   | | |
                   | | |--47.38%-- sclhi
                   | | | |
                   | | | |--88.80%-- i2c_outb
...
     2.20% kworker/0:0 [kernel.kallsyms] [k] na
                |
                --- native_read_tsc
                   |
                   |--64.58%-- delay_tsc
                   | |
                   | |--63.38%-- __udelay
                   | | |
                   | | |--47.18%-- i2c_outb.isra.4
                   | | | try_address
                   | | | bit_doAddress.isra.7
                   | | | bit_xfer
                   | | | intel_i2c_quirk_xfer
...

I've attached the entire perf report output for your analysis.

To view the stack of the process I ran cat /proc/16287/stack > pid-16287-stack.txt, which is also attached.

Please fix the Intel driver so that it does not spawn any wild kworker processes and publish the fix in the 12.04 mainline kernel. I've noticed that others have this sympoms too, but I guess few are knowledgeable enough to file a proper bug report, so I decided to do one. For example, see comment #27 at https://bugs.launchpad.net/ubuntu/+source/linux/+bug/887793/comments/27 or http://askubuntu.com/questions/106187/lenovo-thinkpad-l520-slows-down-when-ac-power-adapter-is-plugged-in

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-24-generic 3.2.0-24.37
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
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: otto 1897 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'PCH'/'HDA Intel PCH at 0x93d40000 irq 44'
   Mixer name : 'Intel CougarPoint HDMI'
   Components : 'HDA:111d76e7,1028049b,00100102 HDA:80862805,80860101,00100000'
   Controls : 37
   Simple ctrls : 13
CheckboxSubmission: d8cea1222d756fdd8d727e88eb0e4a11
CheckboxSystem: d00f84de8a555815fa1c4660280da308
Date: Fri May 11 22:05:56 2012
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=affcc5fa-3b4d-40de-aec2-259585dbd9e3
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta amd64 (20110413)
MachineType: Dell Inc. Latitude E5420
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-24-generic root=UUID=0fc070a9-5f2c-41fc-b8f0-6e0a91fa1426 ro quiet i915.semaphores=1 pcie_aspm=force
PulseList:
 Error: command ['pacmd', 'list'] failed with exit code 1: Home directory /home/otto not ours.
 No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-24-generic N/A
 linux-backports-modules-3.2.0-24-generic N/A
 linux-firmware 1.79
SourcePackage: linux
StagingDrivers: mei
UpgradeStatus: Upgraded to precise on 2012-04-09 (31 days ago)
dmi.bios.date: 02/22/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A00
dmi.board.name: 08N8FC
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA00:bd02/22/2011:svnDellInc.:pnLatitudeE5420:pvr01:rvnDellInc.:rn08N8FC:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E5420
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.

[Otto Kekäläinen (otto)]

Second attachment I referred to in original report.

[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 v3.4kernel[1] (Not a kernel in the daily directory). Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag(Only that one tag, please 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.

http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.4-rc7-precise/

[Otto Kekäläinen (otto)]

Yes, I could try the mainline kernel, but unlike previous rc-folders, http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.4-rc7-precise/ only contains one header package, no kernel-image. Is this intentional?

Also, trough rc1-7 there has been a weekly cadence, but since rc7 it stopped. Is the build process broken etc..?

[Joseph Salisbury (jsalisbury)]

You can now get v3.4 final at:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.4-quantal/

[Otto Kekäläinen (otto)]

kernel-bug-exists-upstream

[Otto Kekäläinen (otto)]

I've now been running the kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.4-quantal/ and I confirm the bug still exists.

I tried to add the tag kernel-bug-exists-upstream but the Launchpad UI does not have a field for that, so I don't know how to do it.

[Otto Kekäläinen (otto)]

As the bug existed in the mainline kernel, I went back to standard Ubuntu 12.04 LTS to get all security updates etc. I recently installed all upgrades and the situation got worse. Now if I plug in the power cord the system slows down so much that using it comes unbearable.

Running:
Linux Latitude-E5420 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:30:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

I'll reinstall the 3.4 mainline kernel as it is was a little bit more usable.

[Otto Kekäläinen (otto)]

I just installed kernel 3.5 from http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5-quantal/ on my Ubuntu 12.04 and the bug is still present.

I am really annoyed by this bug and I waste a lot of time each day or have to make special preparations not to have to ever load the batter while trying to work.

I really hope somebody would fix this bug because protection from bad hardware drivers was the main motivation I bought an certified Dell computer with pre-installed Ubuntu in the first place.

[fabien c (fabien-acathla)]

Hi,
I have the same laptop at work (E5420) and the same bug, but it's nothing compared to the Samsung NP-R530-JA06FR :
The Dell is lagging only when battery is charging, the bug on the Samsung is random, so it's unusable.
I tried Ubuntu 12.04, 12.10, amd64 and i386 versions, xubuntu 12.04, the last 3.8.1 kernel and many others. Same results.

The origin of the lag seems to be the same for the two laptops : Intel I²C
perf report extract on the samsung:
- 23,17% kworker/0:1 [i915] [k] get_clock
   - get_clock
      - 99,63% sclhi
         + 80,31% i2c_outb.isra.0
         + 19,69% i2c_stop
- 18,19% kworker/1:2 [i915] [k] get_clock
   - get_clock
      - 99,75% sclhi
         + 80,22% i2c_outb.isra.0
         + 19,78% i2c_stop
+ 8,90% kworker/0:1 [kernel.kallsyms] [k] native_read_ts
+ 7,03% kworker/1:2 [kernel.kallsyms] [k] native_read_ts
+ 4,94% kworker/0:1 [kernel.kallsyms] [k] delay_tsc
+ 4,67% swapper [kernel.kallsyms] [k] read_hpet

Is there a way to fix this, even by disabling something like autodetection of external screens?
I tried Option "HotPlug" "off" in xorg.conf but it's not enough.

[Karl Hunt (karlgeorgehunt-7)]

I also have an E5420 and I have the exact same issue. It is really annoying. There used to be a work around

echo N> /sys/module/drm_kms_helper/parameters/poll

This would fix the slow downs but had other side effects like not detecting displays automatically etc.

This should not be a "Certified for Ubuntu" Laptop it quite obviously has not been tested!

[penalvch (penalvch)]

Otto Kekäläinen, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p linux <replace-with-bug-number>

Also, could you please test the latest upstream kernel available following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Please do not test the daily folder, but the one all the way at the bottom. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-v3.11-rc5

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

[Otto Kekäläinen (otto)]

I got tired of this buggy laptop so I gave it away and bought a new Dell XPS 13 with preinstalled Ubuntu. It sometimes also freezes, but I don't have time to debug everything. I really hope that in the future all pre-installed Ubuntu machines I buy would work perfectly. Thanks for your efforts towards that!

[Karl Hunt (karlgeorgehunt-7)]

I have this laptop and this is still an issue in an up to date
ringtail installation. If anything the bug has got worse the laptop
completely freezes with power adapter in and the old dkms work around
no longer works either.

Sent from my iPad

On 25 Aug 2013, at 01:50, "Christopher M. Penalver"
<email address hidden> wrote:

Otto Kekäläinen, this bug was reported a while ago and there hasn't been
any activity in it recently. We were wondering if this is still an
issue? If so, could you please test for this with the latest development
release of Ubuntu? ISO images are available from
http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in
the development release from a Terminal
(Applications->Accessories->Terminal), as it will automatically gather
and attach updated debug information to this report:

apport-collect -p linux <replace-with-bug-number>

Also, could you please test the latest upstream kernel available
following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow
additional upstream developers to examine the issue. Please do not
test the daily folder, but the one all the way at the bottom. Once
you've tested the upstream kernel, please comment on which kernel
version specifically you tested. If this bug is fixed in the mainline
kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested.
For example:
kernel-fixed-upstream-v3.11-rc5

This can be done by clicking on the yellow circle with a black pencil
icon next to the word Tags located at the bottom of the bug
description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's
Status as Confirmed. Please let us know your results. Thank you for your
understanding.

** Tags added: bios-outdated-a13 regression-potential

** Changed in: linux (Ubuntu)
      Status: Confirmed => Incomplete

--
You received this bug notification because you are subscribed to the bug
report.
https://bugs.launchpad.net/bugs/998204

Title:
 Intel chipset driver bug on Ubuntu certified Dell Latitude E5420:
 connecting power cord makes kworker run amok

Status in “linux” package in Ubuntu:
 Incomplete

Bug description:
 I've noticed that sometimes when I'm running on battery and then
 insert the power cord, the system slows down significantly. When I
 remove the power cord, it runs fine again, and when I reattach the
 power cord the system slows down again.

 I'm running the latest Ubuntu 12.04 with all updates on a pre-
 installed Dell Latitude E5420 that is supposed to work perfectly with
 Ubuntu, since it is officially certified.

 While the sluggishness happens, running 'top' shows several kworker processes:
 top - 21:29:24 up 14:01, 4 users, load average: 1.91, 2.16, 2.06
 Tasks: 208 total, 3 running, 202 sleeping, 0 stopped, 3 zombie
...

[penalvch (penalvch)]

Otto Kekäläinen, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/linux/+bug/998204/comments/13 regarding you no longer have the hardware. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status. Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.

Karl Hunt, 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 documention 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.