kernel-image-std-def-2.6.24-alt6 Dell Latitude D610 After ca. 20 sec after unplugging AC, the CPU frequency becomes the highest (2GHz) (instead of remaining the lowest 800Mhz) and permanently remains high if being in X (the current console is X; if I switch consoles, the frequency usually switches to the correct 800Mhz). I noticed this in Gnome. Then I did more clean experiments, on freshly booted system, with all frequency daemons turned off (no powersaved, cpufreqd, cpuspeed) and no Gnome. (But from my experience in Gnome I know that the frequency really stays permanently high although there is no CPU load all this time.) All 4 governer modules have been loaded (through /etc/modules): # lsmod | fgrep cpu cpufreq_stats 10272 0 acpi_cpufreq 13836 0 xt_tcpudp 7296 7 x_tables 19204 6 ipt_REJECT,ipt_LOG,xt_tcpudp,xt_state,xt_multiport,ip_tables processor 40680 3 acpi_cpufreq,thermal cpufreq_userspace 8836 0 cpufreq_powersave 5760 0 cpufreq_ondemand 12684 0 freq_table 8960 3 cpufreq_stats,acpi_cpufreq,cpufreq_ondemand cpufreq_conservative 11784 1 # echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor # In linux console, the frequency usually goes up after 20 sec, but then usually in about a minute goes down. In X, it goes up, and the usually remains high. I did the experiment in a clean X (started by xinit, with only an xterm): Steps to Reproduce: Script started on Fri Mar 28 06:33:00 2008 [root@dell ~]# cpufreq-info ; date cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006 Report errors and bugs to linux@brodo.de, please. analyzing CPU 0: driver: acpi-cpufreq CPUs which need to switch frequency at the same time: 0 hardware limits: 800 MHz - 2.00 GHz available frequency steps: 2.00 GHz, 1.60 GHz, 1.33 GHz, 1.07 GHz, 800 MHz available cpufreq governors: userspace, powersave, ondemand, conservative, performance current policy: frequency should be within 800 MHz and 2.00 GHz. The governor "ondemand" may decide which speed to use within this range. current CPU frequency is 800 MHz (asserted by call to hardware). Fri Mar 28 06:33:11 MSK 2008 [root@dell ~]# date # unplugging Fri Mar 28 06:33:17 MSK 2008 [root@dell ~]# cpufreq-info ; date cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006 Report errors and bugs to linux@brodo.de, please. analyzing CPU 0: driver: acpi-cpufreq CPUs which need to switch frequency at the same time: 0 hardware limits: 800 MHz - 2.00 GHz available frequency steps: 2.00 GHz, 1.60 GHz, 1.33 GHz, 1.07 GHz, 800 MHz available cpufreq governors: userspace, powersave, ondemand, conservative, performance current policy: frequency should be within 800 MHz and 800 MHz. The governor "ondemand" may decide which speed to use within this range. current CPU frequency is 800 MHz (asserted by call to hardware). Fri Mar 28 06:33:21 MSK 2008 [root@dell ~]# cpufreq-info ; date cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006 Report errors and bugs to linux@brodo.de, please. analyzing CPU 0: driver: acpi-cpufreq CPUs which need to switch frequency at the same time: 0 hardware limits: 800 MHz - 2.00 GHz available frequency steps: 2.00 GHz, 1.60 GHz, 1.33 GHz, 1.07 GHz, 800 MHz available cpufreq governors: userspace, powersave, ondemand, conservative, performance current policy: frequency should be within 800 MHz and 2.00 GHz. The governor "ondemand" may decide which speed to use within this range. current CPU frequency is 2.00 GHz (asserted by call to hardware). Fri Mar 28 06:33:41 MSK 2008 [root@dell ~]# cpufreq-info ; date cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006 Report errors and bugs to linux@brodo.de, please. analyzing CPU 0: driver: acpi-cpufreq CPUs which need to switch frequency at the same time: 0 hardware limits: 800 MHz - 2.00 GHz available frequency steps: 2.00 GHz, 1.60 GHz, 1.33 GHz, 1.07 GHz, 800 MHz available cpufreq governors: userspace, powersave, ondemand, conservative, performance current policy: frequency should be within 800 MHz and 2.00 GHz. The governor "ondemand" may decide which speed to use within this range. current CPU frequency is 2.00 GHz (asserted by call to hardware). Fri Mar 28 06:33:43 MSK 2008 [root@dell ~]# cpufreq-info ; date cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006 Report errors and bugs to linux@brodo.de, please. analyzing CPU 0: driver: acpi-cpufreq CPUs which need to switch frequency at the same time: 0 hardware limits: 800 MHz - 2.00 GHz available frequency steps: 2.00 GHz, 1.60 GHz, 1.33 GHz, 1.07 GHz, 800 MHz available cpufreq governors: userspace, powersave, ondemand, conservative, performance current policy: frequency should be within 800 MHz and 2.00 GHz. The governor "ondemand" may decide which speed to use within this range. current CPU frequency is 2.00 GHz (asserted by call to hardware). Fri Mar 28 06:34:20 MSK 2008 # Actual Results: The frequency remains high. (But switching consoles makes it low. And sometimes running powertop makes it low. Sometimes it even goes low without any special actions, but this is rare.) Expected Results: With no CPU load, the frequency is the lowest (800Mhz).
Workaround: use the conservative governor. (I experience no such problems with it.)
Try with new kernel(2.6.25-alt1)
ping
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