x201 iwlwifi drops out under heavy load

[Martin Pool]

On a Thinkpad x201, on today's Precise:

wifi works reliably in general, but under heavy load it will fail: receiving no traffic, but not giving any obvious errors

To produce enough load, I started downloading several Ubuntu ISOs from remote servers. This works for a variable period of time, sometimes a few minutes, topping out at 2MB/s, which is about my ADSL peak speed.

At moderate load it can work all day, including across suspend/resume cycles, so at least the symptoms are different to bug 948235 and bug 956401, though perhaps the cause is the same.

Running 'sudo rmmod iwlwifi && sudo modprobe iwlwifi' gets it working again.

This seems like it might be a regression but I'm not sure. I'll try an old kernel.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image (not installed)
ProcVersionSignature: Ubuntu 3.2.0-18.29-generic 3.2.9
Uname: Linux 3.2.0-18-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.94.1-0ubuntu2
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: mbp 2516 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf2520000 irq 45'
   Mixer name : 'Intel IbexPeak HDMI'
   Components : 'HDA:14f15069,17aa2155,00100302 HDA:80862804,17aa21b5,00100000'
   Controls : 14
   Simple ctrls : 6
Card29.Amixer.info:
 Card hw:29 'ThinkPadEC'/'ThinkPad Console Audio Control at EC reg 0x30, fw 6QHT33WW-1.14'
   Mixer name : 'ThinkPad EC 6QHT33WW-1.14'
   Components : ''
   Controls : 1
   Simple ctrls : 1
Card29.Amixer.values:
 Simple mixer control 'Console',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Date: Fri Mar 16 17:29:05 2012
HibernationDevice: RESUME=UUID=0cb56ab7-6b06-46a9-bc17-9de56aae544a
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120128)
MachineType: LENOVO 3249CTO
ProcEnviron:
 LANGUAGE=en_AU:en
 TERM=xterm
 PATH=(custom, user)
 LANG=en_AU.UTF-8
 SHELL=/usr/bin/zsh
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.2.0-18-generic root=/dev/mapper/sda6_crypt ro rootflags=subvol=@ quiet splash drm.debug=0xe vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-18-generic N/A
 linux-backports-modules-3.2.0-18-generic N/A
 linux-firmware 1.71
SourcePackage: linux
StagingDrivers: mei
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/31/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 6QET66WW (1.36 )
dmi.board.name: 3249CTO
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:bvr6QET66WW(1.36):bd05/31/2011:svnLENOVO:pn3249CTO:pvrThinkPadX201:rvnLENOVO:rn3249CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 3249CTO
dmi.product.version: ThinkPad X201
dmi.sys.vendor: LENOVO

[Martin Pool (mbp)]

It looks like (bearing in mind this is somewhat intermittent) that this problem does not exist in the upstream kernel:

Linux joy 3.3.0-030300rc7-generic #201203101735 SMP Sat Mar 10 22:36:28 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

(at least, I have downloaded a few hundred MB at 1.5MB/s over wireless with no problems yet.)

[Martin Pool (mbp)]

actually, the upstream kernel does eventually suffer the same problem

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report at bugzilla.kernel.org [1]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

If you are comfortable with opening a bug upstream, It would be great if you can report back the upstream bug number in this bug report. That will allow us to link this bug to the upstream report.

[1] https://wiki.ubuntu.com/Bugs/Upstream/kernel

[Martin Pool (mbp)]

done, https://bugzilla.kernel.org/show_bug.cgi?id=42952

[Martin Pool (mbp)]

ftr, this is still happening on current Precise.

[Joseph Salisbury (jsalisbury)]

The v3.6-rc1[0] kernel is now available. Can you test that kernel to see if this bug has been fixed upstream as of yet.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc1-quantal/

[Martin Pool (mbp)]

ok, i'll test it

[Martin Pool (mbp)]

wifi doesn't work at all on that kernel, see attached dmesg

[Martin Pool (mbp)]

The bug's intermittent so it's hard to say for sure, but it _seems_ to
be working ok in

3.6.0-030600-generic #201209302035

from the quantal kernel ppa. Hooray!

[Martin Pool (mbp)]

Still seems ok after further testing on 3.6.0-030600-generic

  status fixreleased