04 June, 2007

HP-Compaq nx7400 SpeedStep under Linux

$ sudo modprobe speedstep_centrino
FATAL: Error inserting speedstep_centrino (/lib/modules/2.6.20-gentoo-r7/kernel/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.ko): No such device

That's what happened when I tried to set up CPU frequency scaling under Linux on a nx7400 notebook. It turns out that it was shipped with a buggy BIOS (rev f.07). After upgrading to f.0B, the module happily loaded. However as speedstep_centrino is deprecated in newer kernels in favour of acpi_cpufreq, so I recommend using it instead. Works as advertised, the ondemand governor scales between 800MHz and 1.73GHz like a charm.

The BIOS upgrade also helps with the bad state problem that's causing very slow boots and makes going to sleep mode impossible. Previously only the turning off, unplugging A/C and removing battery procedure could reset the machine to normal beaviour.