[natty] internet connection goes down and kworker/u:2 process slows down the system with the kernel Linux 2.6.38

[shishimaru]

I have a bad issue with the kernel 2.6.38. I've also tried it on Maverick, and the problem is still the same.
in an unspecified time, all of a sudden the connections via wi-fi totally disappear and the process kworker/u:2 begins to "eat" my cpu slowly. I can see it with the 'top' command on gnome-terminal. It uses more or less 100% of the cpu, then it goes down again and so on. The problem appears only with the kernel Linux 2.6.38-1, 2.6.38-2 and 2.6.38-3 .
Looks like it's "ath5k phy0: gain calibration timeout".

[shishimaru (shishimaru)]

Same issue with 2.6.38-4 too.

[Krisztian Poos (rocky-poos)]

Hello everyone, I also have the issue on a Thinkpad T500.
Rolling back to 2.6.35 did not solved it, but on 2.6.34 I don't have the issue. upgrading to 2.6.39-02063903 also did not solve the issue. however on my laptop it is quite better than the with the default kernel in natty. The system was unusable with the default one. The issue also exists in Maverick with kernels older than 2.6.35

I also opened a bug uploaded also about the same topic: it can be related to this I guess: Bug #772704

I may think that it may somehow related also to the wifi card/driver, as usually during these periods when kworker eats up my cpu (it uses more than 50% of the cputime) the system often dropped from the wifi access point as well.

If anyone has a solution, it would be great to have, as this is a really annoying issue, and makes working impossible on the system.

Thanks and regards,
RockY

[Krisztian Poos (rocky-poos)]

"kernels older than 2.6.35" -- > newer. sorry.

[Krisztian Poos (rocky-poos)]

11.10 Beta is also affected... I upgraded with big hope... the issue is still here with kernel 3.0.0.8 also unfortunately... :(

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. 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. Please let us know your results.

Thanks in advance.

[penalvch (penalvch)]

shishimaru, thank you for reporting this and helping make Ubuntu better. 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? Can you try with the latest development release of Ubuntu? ISO CD images are available from http://cdimage.ubuntu.com/releases/ .

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

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

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. 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. Please let us know your results.

Thanks in advance.