Bug#401979: /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq not working properly on Centrino Banias

[Mattia Dongili <malattia@linux.it>]

On Thu, Dec 07, 2006 at 07:49:19PM +0100, Mattia Dongili wrote:
> On Thu, Dec 07, 2006 at 06:15:12AM +0200, Jos??? Antonio Insua wrote:
> > Package: linux-image-2.6.18-3-686
> > Version: 2.6.18-7
> > 
> > Hello!
> > 
> > I'm not able to set /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq to 
> > more than 1000 MHz  ( the max frequency of my CPU is 1500 MHz ).
> > 
> > I am using Debian Etch with the 2.6.18-3-686 precompiled kernel from unstable 
> > in an IBM X31 laptop ( Centrino Banias 1500 MHz ).
> > 
> > At the end comes the result of cat /proc/cpuinfo,  lspci and dmesg in my 
> > machine.
> > 
> > I'm able to solve the problem compiling a new kernel without the option 
> > X86_SPEEDSTEP_CENTRINO_ACPI. The needed option is 
> > X86_SPEEDSTEP_CENTRINO_TABLE. I'm also experimenting the problem when I 
> > compile the kernel with both options.
> > 
> > I would gladly help you in anything I can.
> 
> Don't know if it applies or is valid, but it sounds like this patch
> could help there:
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.19-rc6/2.6.19-rc6-mm2/broken-out/cpufreq-fix-bug-in-duplicate-freq-elimination-code-in-acpi-cpufreq.patch

hmmm, I did look at the code, on a clean 2.6.19 this patch doesn't apply
(depends on a bigger acpi-cpufreq rework).

You may want to build the kernel with CPUFREQ_DEBUG=y and boot with
cpufreq_debug=7
Post the resulting boot log (dmesg), it will contain much more useful
info.

Thanks
-- 
mattia
:wq!