Re: 2.5.69 strange high tone on DELL Inspiron 8100

From: Troels Walsted Hansen (troels@thule.no)
Date: Tue May 13 2003 - 07:43:49 EST


Andrew McGregor wrote:
> Try this (which will make no difference to the effectiveness of APM on
> this machine):
>
>> CONFIG_PM=y
>>
>> CONFIG_APM=y
>> CONFIG_APM_DO_ENABLE=n
>> CONFIG_APM_CPU_IDLE=n
>> CONFIG_APM_DISPLAY_BLANK=y
>> CONFIG_APM_REAL_MODE_POWER_OFF=y
>>
>> CONFIG_CPU_FREQ=n
>> CONFIG_CPU_FREQ_TABLE=n
>>
>> CONFIG_X86_SPEEDSTEP=n
>
>
> Reasoning:
> cpufreq and speedstep don't work on Dell P3 laptops anyway, and the
> *internal power supplies* of the i8x00 series make wierd noises when APM
> tries to idle the CPU. The board will do this anyway, without making
> noise, so linux need not.

My Dell Latitude C600 shows the exact same problem. I noticed it after
upgrading to from RH7.x to RH8 with kernel 2.4.18-27.8.0. I believe this
kernel is customized by RH to use HZ=500 or something in that region.

With your analysis of the problem I was able to remove the noise by
using the "apm=idle-threshold=100" parameter on the kernel commandline.
This turns off APM idle calls without requiring kernel recompilation.

Using the "i8k" kernel module, I have verified that the temperature of
the CPU is unchanged with APM idle turned off. I have not tried to
measure power consumption or battery use.

Thanks for the tip!

-- 
Troels Walsted Hansen

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Thu May 15 2003 - 22:00:44 EST