curious behaviour of cpu's fan

curious behaviour of cpu's fan

[Gianko]

Hi, I've just compiled and installed the kernel 2.6.11.7
When I put cpu's clock to half:

[root]# echo 1200000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

cpu's fan go crazy, in other words his rpm increase and reduce cyclically.
The temperature is normal (about 64.0 degrees C).

I've a notebook asus ld3872 with a PIV 2200Mhz and this is my kernel configuration reguarding ACPI

CONFIG_ACPI=y
CONFIG_ACPI_BOOT=y
CONFIG_ACPI_INTERPRETER=y
CONFIG_ACPI_SLEEP=y
CONFIG_ACPI_SLEEP_PROC_FS=y
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_VIDEO=y
CONFIG_ACPI_FAN=y
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_THERMAL=y
CONFIG_ACPI_ASUS=y
# CONFIG_ACPI_IBM is not set
# CONFIG_ACPI_TOSHIBA is not set
CONFIG_ACPI_BLACKLIST_YEAR=0
CONFIG_ACPI_DEBUG=y
CONFIG_ACPI_BUS=y
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_PCI=y
CONFIG_ACPI_SYSTEM=y
# CONFIG_X86_PM_TIMER is not set
# CONFIG_ACPI_CONTAINER is not set

reguarding cpu frequency scaling:

CONFIG_X86_ACPI_CPUFREQ=y
# CONFIG_X86_POWERNOW_K6 is not set
# CONFIG_X86_POWERNOW_K7 is not set
# CONFIG_X86_POWERNOW_K8 is not set
# CONFIG_X86_GX_SUSPMOD is not set
CONFIG_X86_SPEEDSTEP_CENTRINO=y
CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI=y
CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE=y
CONFIG_X86_SPEEDSTEP_ICH=y
# CONFIG_X86_SPEEDSTEP_SMI is not set
CONFIG_X86_P4_CLOCKMOD=y
# CONFIG_X86_CPUFREQ_NFORCE2 is not set
# CONFIG_X86_LONGRUN is not set
# CONFIG_X86_LONGHAUL is not set

# CONFIG_X86_ACPI_CPUFREQ_PROC_INTF is not set
CONFIG_X86_SPEEDSTEP_LIB=y
CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK=y

I hope somebody help me.
Ciao, Giancarlo.

Re: curious behaviour of cpu's fan

[Gianko]

Another curious event is caused by kacpi kernel's process which has an high cpu usage, about 67%.

Giancarlo.