Kernel does not reach power-state C3 and C4 with loaded modules "ehci-hcd" and "uhci-hcd"

Bug #332125 reported by Stefan Glasenhardt on 2009-02-20
Affects Status Importance Assigned to Milestone
linux (Ubuntu)

Bug Description

Binary package hint: linux-image-2.6.28-8-generic


kernel 2.6.28 does not allow the CPU to reach power-states C3 and C4 an my notebook, when the kernel modules "ehci-hcd" and "uhci-hcd" are loaded. If i unload them, C3 and C4 are reached. This was not the case with kernel-version 2.6.27 from Intrepid. Early version of the Ubuntu-kernel 2.6.28 (e.g. "-1" or "-2"), allowed C3 and C4 when i unloaded "uhci-hcd" and kept "ehci-hcd", but newer version never reach C3 and C4 when both modules are loaded.

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
MachineType: Dell Inc. Latitude D505
Package: linux-image-2.6.28-8-generic 2.6.28-8.24
ProcCmdLine: root=/dev/sda1 ro hpet=force quiet
ProcVersionSignature: Ubuntu 2.6.28-8.24-generic
SourcePackage: linux

Stefan Glasenhardt (glasen) wrote :
Jeremy Foshee (jeremyfoshee) wrote :

Hi Stefan,

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

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 332125

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 . 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.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

tags: added: needs-kernel-logs
tags: added: needs-upstream-testing
tags: added: kj-triage
Changed in linux (Ubuntu):
status: New → Incomplete
Stefan Glasenhardt (glasen) wrote :

Hi Jeremy,

You can close this bug or mark it invalid. Since Karmic the kernel allows the C3/C4-state again. It seems that my notebook does not allow the lowest CPU-states if any USB1.1-device is present.

Greetings Stefan

Jeremy Foshee (jeremyfoshee) wrote :

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 . 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.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

tags: added: kj-expired
Changed in linux (Ubuntu):
status: Incomplete → Expired
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