/sys/module/pcie_aspm/parameters/policy not settable

[CatchesAStar]

From: http://ubuntuforums.org/showthread.php?t=2010191

The parameters in /sys/module/pcie_aspm/parameters/policy are not settable.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1017746

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Dirk F (fieldhouse)]

This sort of thing can happen:

root:~# echo default > /sys/module/pcie_aspm/parameters/policy
-bash: echo: write error: Operation not permitted

For instance, the pmutils script normally installed at /usr/lib/pm-utils/power.d/pcie_aspm, which is executed on every change between mains and battery operation, can exhibit such behaviour.

Even when pcie_aspm modes are offered the ability to set them may be disabled, and the pcie_aspm sysfs interface doesn't offer a way to tell that this is so.

See http://smackerelofopinion.blogspot.co.uk/2011/03/making-sense-of-pcie-aspm.html for technical background on why setting the pcie_aspm mode might be disabled.

In short "this behaviour is by design".