iwlwifi + intel 6205 + tp-link 4300: bandwidth changed = host unreachable

[Constantine Peresypkin]

when using the combo of Intel 6205N (IBM ThinkPad T430s) and TP-Link TL-WDR4300 router there is a problem of sudden loss of connectivity after a "bandwidth change" event is registered by wifi module.

In log:
Feb 10 13:09:28 lenovo kernel: [1981878.856612] wlan0: AP <redacted> changed bandwidth, new config is 2462 M
Hz, width 1 (2462/0 MHz)
Feb 10 13:09:31 lenovo kernel: [1981881.929193] wlan0: AP <redacted> changed bandwidth, new config is 2462 M
Hz, width 2 (2452/0 MHz)

After that point no frames are coming from the router. I.e. even ARP is not resolving, although the wifi connection seems to look fine in NetworkManager. Restarting networking or killing wpa_supplicant solves the problem for a while.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-extra-3.13.0-38-generic 3.13.0-38.65
ProcVersionSignature: Ubuntu 3.13.0-45.74-generic 3.13.11-ckt13
Uname: Linux 3.13.0-45-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.7
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: kit 2467 F.... pulseaudio
CRDA:
 country IL:
  (2402 - 2482 @ 40), (N/A, 20)
  (5150 - 5250 @ 40), (N/A, 23), NO-OUTDOOR
  (5250 - 5350 @ 40), (N/A, 23), NO-OUTDOOR, DFS
CurrentDesktop: Unity
Date: Tue Feb 10 13:19:45 2015
HibernationDevice: RESUME=UUID=5719e2ac-f0f6-464f-99cf-f732c3ec9606
InstallationDate: Installed on 2014-01-28 (378 days ago)
InstallationMedia: Ubuntu 12.04.3 LTS "Precise Pangolin" - Release amd64 (20130820.1)
MachineType: LENOVO 235389G
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-45-generic.efi.signed root=UUID=0c5e577c-b641-490c-ae43-f88b134fe24a ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-45-generic N/A
 linux-backports-modules-3.13.0-45-generic N/A
 linux-firmware 1.127.11
SourcePackage: linux
UpgradeStatus: Upgraded to trusty on 2014-09-07 (156 days ago)
dmi.bios.date: 02/18/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: G7ET92WW (2.52 )
dmi.board.asset.tag: Not Available
dmi.board.name: 235389G
dmi.board.vendor: LENOVO
dmi.board.version: Win8 Pro DPK TPG
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG7ET92WW(2.52):bd02/18/2013:svnLENOVO:pn235389G:pvrThinkPadT430s:rvnLENOVO:rn235389G:rvrWin8ProDPKTPG:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 235389G
dmi.product.version: ThinkPad T430s
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[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 v3.19 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/v3.19-vivid/

[Constantine Peresypkin (constantine-q)]

It's very hard to reproduce, unfortunately. Sometimes it happens number of times per day, sometimes it's a month without problems.

[Launchpad Janitor (janitor)]

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

[David Feeney (david-feeney)]

Hello,

I do experience precisely the same error on a Lenovo Thinkpad x230 with kubuntu 15.04. The x230 has the Centrino Advanced 6205 N wifi chipset. The error did not occur with Debian 7, I had this set up on the machine before.

The bug really is extremely menacing, one is forced to reconnect multiple times per day, sometimes every ten minutes or so. I am glad to finally see a bug report.

[David Feeney (david-feeney)]

Further info: this bug does not occur in every WLAN.

[David Feeney (david-feeney)]

Dear ubuntu developers, dear crowd,

I really love you for the time you put into OSS. I myself am struggling with learning coding, and by that I am refering to the likes of Python and BASH. I could do nothing (or very, very litte) to troubleshoot a wifi kernel module.

However, this Bug is so profoundly annoying and harmful - what good is a PC without net connection? If you are reading this and happen to be a dev with little time, but have any idea of what might be useful research, please tell me. I have used arch linux for a year and had a debian machine with compiled kernels, so if you tell me where I can find useful docs I will do anything ;-)

To wit, I have tried the 11n=disable module option. The issue with my lenovo x230 / Intel Centrino Advanced-N 6205 [Taylor Pe
ak] (rev 34) must lie somewhere else.

Thanks for reading!

[David Feeney (david-feeney)]

Update: With Kernel 4.2 rc7, this problem stopped. Message is still being displayed, but the bandwidth does not deteriorate anymore. Great improvement!