Re: Cpufreq on kernel 2.6.18

[Joan Moreau <joan.moreau@m4x.org>]

Thanks for the tip.

I guess the error comes from the Kernel, as all interfaces are their, 
but the frequency is not changeable in /sysfs :-(



Pallipadi, Venkatesh wrote:
>  
>
>   
>> -----Original Message-----
>> From: Joan Moreau [mailto:joan.moreau@m4x.org] 
>> Sent: Sunday, October 08, 2006 1:25 PM
>> To: Luca
>> Cc: Pallipadi, Venkatesh; cpufreq@lists.linux.org.uk
>> Subject: Re: Cpufreq on kernel 2.6.18
>>
>> Luca,
>>
>> I have exactly the same problem on my pentium M 2Ghz.
>>
>> Only "cpufreq_centrino"  works under linux 2.6.18 (i..e /sys has 
>> relevant info) but cpufredq does not work anymore (frequancy 
>> not changeable)
>>
>> Has anybody found any fixes ?
>>
>> Thanks
>>
>> Joan
>>     
>
> The change from acpi-cpufreq to speedstep-centrino driver from 2.6.16 to
> 2.6.18 is intentional. Looks like your platform can support both these
> drivers and Linux is picking the best driver, that is speedstep centrino
> in this case. So, everything is fine until that point.
>
> But, I don't know why cpufreqd does not work with speedstep-centrino. As
> long as these /sysfs interfaces are there, cpufreqd should work. Is it
> not inserting the speedstep-module and hence it is failing? Can you try
> manually switching to performance and powersave governors and make sure
> frequency is changing. Something like this after you have
> speedstep_centrino working.
>
> #cd /sys/devices/system/cpu/cpu0/cpufreq
> // I am assuming that this is a Centrino CPU with single logical CPU.
> #cat  scaling_available_frequencies
> #echo performance > scaling_governor
> #cat cpuinfo_cur_freq
> #echo powersave > scaling_governor
> #cat cpuinfo_cur_freq
>
> Now if this works, you can go ahead and try ondemand governor and see
> whether that is working
> #echo ondemand > scaling governor
> // Leave system idle for couple of seconds
> #echo cpuinfo_cur_freq
> // Run some infinite loop code or some other load to keep CPU busy
> #echo cpuinfo_cur_freq
>
> Now if this also works, then there is something wrong with cpufreqd..
> If any of these doesn't work, then there is some problem in kernel.
>
> Thanks,
> Venki
>
>