CPU not going in C3 after hibernate

The Hardy Heron Alpha2 release will be coming out soon (around Dec 20). It will have an updated version of the kernel. It would be great if you could test with this new release and verify if this issue still exists. I'll be sure to update this report when Alpha2 is available. Thanks!

I'm opened a new task against the actively developed kernel. However, I'm closing the report against linux-source-2.6.22 as it does not meet the criteria for a stable release update. You can learn more about the stable release update process at https://wiki.ubuntu.com/StableReleaseUpdates . Thanks!

I've installed Hardy and tested it, but the new kernel didn't solve the problem.

Thanks for testing. Per the kernel team's bug policy, can you please attach the following information:

* uname -a > uname-a.log
* cat /proc/version_signature > version.log
* dmesg > dmesg.log
* sudo lspci -vvnn > lspci-vvnn.log

Please be sure to attach each file as a separate attachment. It would be good to capture your dmesg output after you experience your issue. That way we can hopefully catch any useful messages in the log. For more information regarding the kernel team bug policy, please refer to https://wiki.ubuntu.com/KernelTeamBugPolicies . Thanks again and we appreciate your help and feedback.

Thanks Matteo,

I'm reassigning to the kernel team. Thanks!

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

Ok, I'll test the 2.6.27 kernel when I have time. The 2.6.27 packages for hardy are the ones specified here:
http://blog.phunnypharm.org/2008/08/2627-rc3-kernel-images-for-hardy804-and.html

Otherwise where I can found the packages?

I'm running the 2.6.26-5 ubuntu kernel compiled by myself some time ago but it doesn't fix this issue.

I've built my own 2.6.27-2 kernel for hardy and the problem is still there.

I've also found that the problem isn't strictly related to hibernation, but also apply to suspend.
If I do: suspend -> unplug -> resume actually the system doesn't go in C3.

Is a normal behaviour that the cpu doesn't go in C3 when the AC is plugged?

I'm having this issue as well with kernel version 2.6.27-7 on Intrepid. Powertop doesn't show the C3 state at all after suspend/hibernation, and when I restart my computer, C3 is being used.

@Matteo Collina
It is normal for the cpu to not go into C3 when on AC power. It's a performance versus power consumption balancing act that on AC power, the computer's performance not be affected, and on battery power, performance is reduced to increase battery life. It takes more time to wake out of C3 than C2 even though C3 saves power, so C3 is never entered on AC but is on battery.

I wish I could take back what I said earlier "Powertop doesn't show the C3 state at all after suspend/hibernation..."

I'm actually only having issues with suspend and not hibernate on this bug on Intrepid Ibex. It seems like 2.6.27-7 has fixed the hibernation problem but not suspend.

@krlhc8
I know it and it's fine. This issue is different: the kernel at resume doesn't check if we're on ac or battery and disable/enable C3 state basing on this. It just restores the last state.

Per a decision made by the Ubuntu Kernel Team, bugs will longer be assigned to the ubuntu-kernel-team in Launchpad as part of the bug triage process. The ubuntu-kernel-team is being unassigned from this bug report. Refer to https://wiki.ubuntu.com/KernelTeamBugPolicies for more information. Thanks.

This bug report was marked as Triaged a while ago but has not had any updated comments for quite some time. Please let us know if this issue remains in the current Ubuntu release, http://www.ubuntu.com/getubuntu/download . If the issue remains, click on the current status under the Status column and change the status back to "New". Thanks.

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This bug report was marked as Incomplete and has not had any updated comments for quite some time. As a result this bug is being closed. Please reopen if this is still an issue in the current Ubuntu release http://www.ubuntu.com/getubuntu/download . Also, please be sure to provide any requested information that may have been missing. To reopen the bug, click on the current status under the Status column and change the status back to "New". Thanks.

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