Hardware:HP DV1381,CM 1.5G.
Software:FC6 Test1(FC5 has the same problem),kernel is 2.6.17.
I cannot use cpu frequency scaling.I'm sure I configured the kernel correct.But in the directory /sys/devices/system/cpu/cpu0 there isn't a directory named cpufreq,just a file named crash_notes,in this file just one line:
1f5d3ac4
The service cpufreq is stoped,and cannot be started.
In the log file there is one line:
Jul 6 01:08:34 localhost kernel: ACPI: CPU0 (power states: C1[C1] C2[C2] C3[C3])
Then I download cpufrequtils.When configuring it,such information displayed:
checking sysfs/libsysfs.h usability... no
checking sysfs/libsysfs.h presence... no
checking for sysfs/libsysfs.h... no
*********************************************************************
*** ERROR WHILE CONFIGURING LIBCPUFREQ ***
*** Failed to detect libsysfs header files and/or library ***
*********************************************************************
*********************************************************************
*** ERROR WHILE CONFIGURING LIBCPUFREQ ***
*** At least one of /sys support or /proc support MUST be enabled ***
*********************************************************************
configure: error: At least one of /sys support or /proc support MUST be enabled
configure: error: /bin/sh './configure' failed for libcpufreq

Now I tryed the command:
mount -t sysfs sysfs /sys
It shows the sysfs has already mounted.
What should I do?

Have you tried installing the sysfsutils, which includes libsysfs?

http://linux-diag.sourceforge.net/Sysfsutils.html

There sysfsutils ver 1.3.0 has already installed.Then I upgrade it to ver 2.0.
And also I installed cpufrequtils0.4 and cpufreqd 2.1.1.
I run cpufred,there is nothing output.Using ps -aux show that it is already running.
But when run cpufreq-info it says there is no cpufreqd socket. There is also a crash_note in the directory /sys/devices/system/cpu/cpu0 and hasn't a directory named cpufreq there.

Well I don't know too much about the Celeron M processor, but according to the following review it doesn't support "Enhanced Speedstep":
http://www.mobilityguru.com/2004/03/...ino/index.html

This suggests to me that it doesn't do frequency scaling. You could also check through Intel's datasheet for more details:
http://www.intel.com/design/mobile/datashts/300302.htm

Would you mind giving the output of "cat /proc/cpuinfo | grep stepping"?

Thank you very much.
This is the cpuinfo:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 13
model name : Intel(R) Celeron(R) M processor 1.50GHz
stepping : 8
cpu MHz : 1496.612
cache size : 1024 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 mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx up
bogomips : 2996.84

Ok, you might want to check out the following page by Michael Kupsch about configuring the ThinkPad R50e, which has the same processor:
http://www.mk-stuff.de/artikel/linux...pad_r50e/#freq

In particular, the cpufreqd.conf file.

Finally I made it.
The solution is to choose P4-M instead of PM.I thought the CM and PM are the same type,but I was wrong.
That article about ThinkPad R50e helps me a lot.Now the cpu frequency scaling works fine on my notebook.
You're really a warmhearted man and I would thank you again.