cpufreq dirs in /sys don't show up anymore

Bug #205087 reported by Andres Järv on 2008-03-22
Affects Status Importance Assigned to Milestone
linux (Ubuntu)

Bug Description

Binary package hint: laptop-mode-tools

I found out that 'cat /proc/cpuinfo' shows that my Intel Core2Duo processor is always clocked to 2GHz although I had enabled the "ondemand" governor in laptop-mode configuration. After investigating, I discovered that the cpufreq_ondemand governor wasn't even loaded. After loading it the /sys/devices/system/cpu/cpuX/cpufreq directories didn't show up so setting the governor was still pretty damn impossible even by hand.

I didn't know where to report this since there are like a gazillion apps dealing with ACPI and power management (which seems pretty unreasonable, but that's not the point at the moment) so I reported it under laptop-mode-tools. I have a Dell D630 and this used to work before. I have enabled laptop-mode in /etc/default/acpi-support.

Andres Järv (andresjarv) wrote :

Also, I get this:

$ cat /proc/sys/vm/laptop_mode

Which should mean that laptop mode isn't enabled at all :S

Also, I'm running Hardy i386.

Tormod Volden (tormodvolden) wrote :

/proc/cpuinfo lists the maximum frequency, not the current one. Add the "CPU Frequency Scaling Monitor" applet to your gnome-panel.
You should not need to enable laptop_mode for CPU frequency scaling.

BTW, is this with Hardy and latest kernel?

Changed in laptop-mode-tools:
assignee: nobody → tormodvolden
status: New → Incomplete
Andres Järv (andresjarv) wrote :

I'm using Hardy with KDE4 and the latest kernel. And about /proc/cpuinfo. Hmm.. it always used to show the current frequency for me. With the ondemand governor my Core2Duo was conveniently clocked to 800MHz. Now it just sits on 2GHz all the time which is probably quite a power hog.

Changed in linux:
assignee: tormodvolden → nobody
status: Incomplete → New
Daniel Hahler (blueyed) wrote :

Confirming for 2.6.24-16-generic.
CPU get throttled, according to "grep MHz /sys/devices", but there's no userspace interface.

$ cat /sys/devices/system/cpu/cpuidle/current_driver

$ lsmod | grep cpu
cpufreq_powersave 2688 0
cpufreq_stats 7104 0
cpufreq_userspace 5284 0
cpufreq_ondemand 9740 1
cpufreq_conservative 8712 0
freq_table 5536 3 powernow_k8,cpufreq_stats,cpufreq_ondemand

$ dmesg | egrep 'cpu|power'
[ 39.675102] cpuidle: using governor ladder
[ 39.675150] cpuidle: using governor menu
[ 90.464446] powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3000+ processors (1 cpu cores) (version 2.20.00)
[ 90.464476] powernow-k8: 0 : fid 0xa (1800 MHz), vid 0x6
[ 90.464478] powernow-k8: 1 : fid 0x2 (1000 MHz), vid 0x12

Changed in linux:
importance: Undecided → Medium
status: New → Triaged
fimbulvetr (fimbulvetr) wrote :

I just installed the RC on a D630 this morning. cat /proc/cpuinfo is reflecting that the MHZ is at 800 when idle. Cpu freq monitor from gnome confirms as much.

All files in /sys/devices/system/cpu/cpuX/cpufreq are available, and ondemand is loaded and working.

Daniel Hahler (blueyed) wrote :

Now, for me /sys/devices/system/cpu/cpuX/cpufreq is available again, too.
Maybe it's related to hibernation or something similar?

Andres Järv (andresjarv) wrote :

Hmm. It seems like I just had to install cpufrequtils for it to work. Now the ondemand governor is set correctly.

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.


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.

Andres Järv (andresjarv) wrote :

Yeah, works with 2.6.27 just fine.

Changed in linux:
status: Triaged → Fix Committed

Setting this to "Fix Released" based on the decision to stick with the 2.6.27 kernel for Intrepid - https://lists.ubuntu.com/archives/kernel-team/2008-September/003107.html

Changed in linux:
status: Fix Committed → Fix Released
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