https://community.hpe.com/t5/operating-system-linux/cpu-frequency-scaling-not-supported-on-tc4400/m-p/3934291#M65467 Hi,<BR /><BR />I installed various Linux distributions on my HP TC4400 tablet with T2500 dual core cpu. In all cases I could not get cpu frequency scaling to work. The distributions I tried were Ubuntu 6.10 (with linux kernel 2.6.17) and OpenSUSE 10.2 (kernel 2.6.18) and a new Fedora version.<BR /><BR />I would greatly appreciate any information on why this problem exists and how I can solve it. Under linux my battery lasts approx 2:30 hours while under Windows XP the battery lasts approx 5 hours.<BR /><BR />In detail, what I see is the following (the same situation for all the tried linux distributions):<BR /><BR />- I would expect a directory<BR /> /sys/devices/system/cpu/cpu0/cpufreq/<BR /> but this directory does not exist<BR /><BR />- lsmod lists the following modules which are related to cpufreq: cpufreq_usedspace, cpufreq_stats, freq_table, cpufreq_powersave, cpufreq_ondemand, cpufreq_conservative, speedstep-lib. modprobe on any of these does not show any error messages.<BR /><BR /><BR />- dmesg showed the following information that might be relevant:<BR /><BR />[17179571.852000] ACPI: Looking for DSDT ... not found!<BR />...<BR />[17179573.688000] CPU1: Intel(R) Core(TM) Duo CPU T2500 @ 2.00GHz stepping 0c<BR />...<BR />(and similar for CPU0)<BR /><BR />- trying to run e.g. powernowd or gnome's frequency scaling monitor results in error message "cpu frequency scaling not supported".<BR /><BR />I would be very grateful for help and of course I would be happy to provide more detailed information!<BR /><BR />Dominik<BR /> Mon, 29 Jan 2007 09:31:16 GMT Dominik Stockinger 2007-01-29T09:31:16Z https://community.hpe.com/t5/operating-system-linux/cpu-frequency-scaling-not-supported-on-tc4400/m-p/3934291#M65467 Hi,<BR /><BR />I installed various Linux distributions on my HP TC4400 tablet with T2500 dual core cpu. In all cases I could not get cpu frequency scaling to work. The distributions I tried were Ubuntu 6.10 (with linux kernel 2.6.17) and OpenSUSE 10.2 (kernel 2.6.18) and a new Fedora version.<BR /><BR />I would greatly appreciate any information on why this problem exists and how I can solve it. Under linux my battery lasts approx 2:30 hours while under Windows XP the battery lasts approx 5 hours.<BR /><BR />In detail, what I see is the following (the same situation for all the tried linux distributions):<BR /><BR />- I would expect a directory<BR /> /sys/devices/system/cpu/cpu0/cpufreq/<BR /> but this directory does not exist<BR /><BR />- lsmod lists the following modules which are related to cpufreq: cpufreq_usedspace, cpufreq_stats, freq_table, cpufreq_powersave, cpufreq_ondemand, cpufreq_conservative, speedstep-lib. modprobe on any of these does not show any error messages.<BR /><BR /><BR />- dmesg showed the following information that might be relevant:<BR /><BR />[17179571.852000] ACPI: Looking for DSDT ... not found!<BR />...<BR />[17179573.688000] CPU1: Intel(R) Core(TM) Duo CPU T2500 @ 2.00GHz stepping 0c<BR />...<BR />(and similar for CPU0)<BR /><BR />- trying to run e.g. powernowd or gnome's frequency scaling monitor results in error message "cpu frequency scaling not supported".<BR /><BR />I would be very grateful for help and of course I would be happy to provide more detailed information!<BR /><BR />Dominik<BR /> Mon, 29 Jan 2007 09:31:16 GMT https://community.hpe.com/t5/operating-system-linux/cpu-frequency-scaling-not-supported-on-tc4400/m-p/3934291#M65467 Dominik Stockinger 2007-01-29T09:31:16Z