Latest working kernel version:2.6.20 (Ubuntu 7.04) Earliest failing kernel version:2.6.22 (Ubuntu 7.10) Distribution:Current is Ubuntu 8.04 (2.6.24) Hardware Environment: Laptop: Fujitsu Siemens - Amilo M1425 (CPU = Centrino) Software Environment: Ubuntu Hardy Problem Description: CPU Scaling does not work anymore. Frequency should be 1.70 GHz but is stuck at 600 MHz. I think that newer versions get their information from the BIOS, whereas earlier versions got their information from another place. Steps to reproduce: sudo modprobe acpi-cpufreq gives the following message ==> FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.24-19-386/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): No such device The same message is displayed for all other cpufreq modules.
Hi, Oliview Will you please confirm whether the cpu scaling can work on the 2.6.20 kernel? Please attach the output of acpidump. Will you please enable "CONFIG_CPUFREQ_DEBUG" in kernel configuration and add the boot option of "cpufreq.debug=7"? After the system is booted , please try to load the acpi_cpufreq driver and attach the output of dmesg. ( both 2.6.20 and 2.6.22 are required). Thanks.
Created attachment 16738 [details] acpidump on kernel 2.6.20
Created attachment 16739 [details] acpidump on kernel 2.6.22
Created attachment 16740 [details] acpidump on kernel 2.6.24
Hi ykzhao, I confirm that CPU scaling can work on the 2.6.20 kernel. I have attached for your reference the acpidump for 2.6.20, 2.6.22 and 2.6.24. I know you want the output of 2.6.20 and 2.6.22, but this will be more complicated and lengthy, as I can only boot from CD at the moment and it is difficult to enable kernel options. I will need to find some hard disk and re-install previous versions. I should be able to come back to you during next week. Thank you for your help.
Hi, Oliver thanks for the acpidump info. In fact the acpidump is not related with the OS kernel. So you needn't attach the acpidump obtained on the different kernel. From the acpidump there doesn't exist the following object related with acpi-cpufreq driver. _PSS, _PCT, _PPC So when the acpi-cpuferq driver is loaded, OS will report the following warning message: > FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.24-19-386/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): No such device Anyway, please add the boot option of "cpufreq.debug=7" and attach the output of dmesg.(Both 2.6.20 and 2.6.24 are required). Thanks.
Hi YKZhao, the boot option of "cpufreq.debug=7" is not recognized by default Ubuntu kernel. I need to recompile the kernel before I can do the testing (which can take some time with the CPU frequency set low), but should be able to come back to you before end of the week.
Created attachment 16774 [details] Working Kernel dmesg (2.6.20-17-generic) This is the output of dmesg on a working kernel (2.6.20-17-generic). It seems the module loaded is "speedstep-centrino".
Created attachment 16775 [details] Non-working Kernel dmesg (2.6.20.21-custom) This is the output of dmesg on a non-working kernel (2.6.20.21), compiled with the correct flag and booted with the option "cpufreq.debug=7". Neither "acpi-cpufreq" nor "speedstep-centrino" can be loaded as modules.
Hi YKZhao, I hope this is enough for your information. Thanks in advance for your help.
Hi YKZhao, I found a solution, based on the following page: http://www.amilo-forum.com/topic,1808,-CPU-stuck-at-600Mhz.html I understand: 1) kernel 2.6.20 was specific to Ubuntu. A patch indicated available cpu frequencies. 2) in generic and later ubuntu kernels, available frequencies were given by the bios. The regression problem is therefore Ubuntu, and not a generic kernel problem, aggravated by a bios problem on the kind of laptop I use (Amilo M1425). I think you can close the bug. Thank you very much for your support.
Hi, Olivier Thanks for the info. Will you please use the "speedstep-centrino" driver on the 2.6.22 kernel and see whether the cpufreq still can't work? Thanks.
Hi YKZhao, I cannot load the speedstep-centrino. I get the same message I got with acpi-cpufreq: FATAL:... no such device. I hope this helps.
Hi, Olivier Thanks for your work. From the comment #11 it seems that the problem is related with the bios problem and not a generic kernel problem. So the bug will be rejected.