SMP-enabled kernels need an APM module option to power off on APM-only systems

[M. Vefa Bicakci]

On SMP-enabled kernels, the APM-based power-off is disabled
automatically. Starting with 6.10 (Edgy Eft), Ubuntu began to
ship SMP-enabled kernels as default. This has an impact on
people who use old computers which do not support ACPI
and hence rely on APM to power off automatically after halting.

There is a way to work around this problem, and that is adding
a file in /etc/modprobe.d/ which contains the following lines:

=== 8< ===
options apm smp=1 power_off=1
=== >8 ===

This line tells the APM module to use the power off feature
even if the kernel is an SMP-enabled one.

It would be nice if Ubuntu included an appropriate file in
/etc/modprobe.d with the contents quoted above. This way
users wouldn't have to do anything special to make Ubuntu
power off properly on older computers which support
only APM.

Thanks in advance,

M. Vefa Bicakci

[M. Vefa Bicakci (mvb)]

Update: I discovered that my computer does not power off
because Edgy Eft (6.10) comes with a SMP-enabled kernel.
Dapper Drake (6.06.1) comes with a non-SMP kernel, so
power off worked before upgrading to Edgy Eft.

For the power off to occur, apm module needs to be loaded
with the option(s) smp=1 and/or power_off=1.

It would be nice if the smp=1 and/or power_off=1 options of
the apm module were default in Ubuntu.

[M. Vefa Bicakci (mvb)]

Clarification: Only SMP-enabled kernels need the special
options of the APM kernel module.

Workaround:

Create /etc/modprobe.d/apm with the following contents:

--- cut here ---
options apm smp=1 power_off=1
--- cut here ---

[Matthew Woerly (nattgew)]

Thanks for taking the time to report this bug and helping to make Ubuntu better. You reported this bug a while ago and there hasn't been any activity in it recently. We were wondering is this still an issue for you in Hardy's latest kernel? Thanks in advance.

[Sergio Zanchetta (primes2h)]

The 18 month support period for Edgy Eft 6.10 has reached it's end of life. As a result, we are closing the linux-source-2.6.17 Edgy Eft kernel task.

[Leann Ogasawara (leannogasawara)]

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.

[Nicolas Michel (nicolas-michel)]

I need to say that on Ubuntu 8.04, the bug is still here. I have an old AMD sempron with an apm motherboard, and I need to put options power_off=1 on modprobe.conf to solve the problem. It would be nice don't needing to do that.

[M. Vefa Bicakci (mvb)]

I have updated the bug description to explain the problem clearly.

[Jamie Strandboge (jdstrand)]

This is still an issue with Jaunty:
$ cat /proc/version_signature
Ubuntu 2.6.28-11.41-generic

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]