CPU frequency scaling broken on Pentium M

[MortalKastor]

Binary package hint: linux

On a MSI Mega Book S260 (Pentium M 2Ghz) CPU frequency scaling worked well since Dapper (at least), but is now suddenly broken on a freshly installed Gutsy (from ubuntu-7.10-desktop-i386.iso final). I did not upgrade, I installed on a virgin partition.

$ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 13
model name : Intel(R) Pentium(R) M processor 2.00GHz
stepping : 8
cpu MHz : 798.289
cache size : 2048 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx up est tm2
bogomips : 1598.10
clflush size : 64

$ uname -r
2.6.22-14-generic

[MortalKastor (mortalkastor)]

CPU frequency scaling was disabled in BIOS, but I didn't even get into BIOS settings, the change occured while installing Gutsy Beta : it worked under Feisty, rebooted under Gutsy Beta live DVD, installed it and there was no more frequency scaling.