cpuinfo_max_freq is (really) wrong

Oh, for reference:

[davyd@frobisher cpufreq]$ cat scaling_driver
acpi-cpufreq
[davyd@frobisher cpufreq]$ cat scaling_governor
conservative

Thanks for taking the time to report this bug and helping to make Ubuntu better. With which specific version of the kernel did you notice this issue? Thanks in advance.

Certainly exists in 2.6.20-9-generic, have seen it in previous kernels too. Possibly in all Feisty 2.6.20 kernels.

Please attach (do not paste into comment) the output of the following commands:

dmesg
cat /proc/cpuinfo

Thanks

Ok, this is definitely a problem with your BIOS reporting incorrect information. Check for a BIOS update. The reason you'll see this now in feisty with 2.6.20 is because of the upgraded acpi-cpufreq driver being able to get more info from the BIOS.

Also, I notice you have an oops in your dmesg. Please file a separate bug about that.

Ok, I'll check to see if there is an update BIOS. For future reference, what hints that the BIOS is wrong?

Also, I hadn't spotted that oops, thanks.

I ran the latest BIOS update, but there was no improvement.

FWIW, I have the same problem on an Athlon 2800+ laptop. My max frequency should be 2133 mhz (apprx) but instead it is 1466 (approx). Using cpufreq_set does not work. Echoing the value into scaling_max_freq does not work. I ran cpufreq-info and it reported the hardware was limiting it to 1467. For fun, I booted into Windows and checked with perfmon. It is 1467 there also!! This is either a hardware problem or somehow the bios got altered (certainly Linux would change the bios, would it??). Any suggestions would be welcome, but I thought this might help someone.

Additional info to above:

If I add acpi=off to grub, I get the full 2.13 ghz. I then tried immediately rebooting into windows and re-ran perfmon, but windows was still limited to 1.467 ghz as per above. Perhaps ACPI is broken on this laptop? Also, I tried booting into the live 6.06 CD to see if it was a kernel issue (since it used to run at 2.13 ghz under dapper), but it was still limited to 1.467. This really makes me wonder if Feisty hasn't done something bad to the ACPI in the bios, but I can't imagine it WRITES to the bios. I hope not. Thanks!

I can confirm the same behavior on hardy.

# uname -a
Linux misos-laptop 2.6.24-20-generic #1 SMP Mon Jul 28 13:49:52 UTC 2008 i686 GNU/Linux
# cat cpuinfo_max_freq
1600000
# cat scaling_max_freq
800000