On Tuesday 30 January 2007 12:35, Joe Harvell wrote: > I am trying to enable all the power saving features I can on my Conroe > E6600. After much searching on the web, I am a little confused about > the Linux kernel support for ACPI on the Conroe. > > Here is my setup: > Intel Core2 Duo E6600 > Asus P5-B Deluxe board (Intel P965). > I am running a Gentoo kernel based on 2.6.19.4. > > I have managed to enable EIST using cpufreq with the speedstep-centrino > driver. But my understanding from browsing the ACPI spec is that this > is still within C0, i.e. not much power savings.
Right, P-states are effective only when code is executing, and on this processor (with C1E) will have no effect on idle power. > Here are my questions: > > 1) For P states, which cpufreq driver should I be using? I've heard > speedstep-centrino is deprecated (but only some aspects of it) that are > being moved into acpi-cpufreq. But I can't get acpi-cpufreq to load in > my kernel version. In 2.6.19 I believe that speedstep-centrino is the one to use. The transition to acpi-cpufreq happens in 2.6.20. > Also, I would have thought speedstep-ich would be > the driver, just based on the name. Don't use speedstep-ich. > How do I know (other than trying > all modules to see which one loads) which one I should be using? > 2) What kind of support for C1-C3 does the Conroe have? The ACPI spec > says C2 and C3 require chipset support on the motherboard. Does P965 > have that. Does it matter between boards (e.g. P5B)? I believe that Conroe currently supports just C1 -- this is true for the ones I have. Internally it is an "Enhanced C1" called C1E where the voltage is reduced in C1-- but this is transparent to software, which thinks it is just C1. You can observe this in /proc/acpi/processor/*/power > 3) What versions of the kernel support C1-C3 states? What kernel > options are germane to this? What libraries/tools are involved? C1-C3 have been supported for a long time. 2.6.20 adds a few tweaks to use a more efficient implementation, but you'll not notice a difference on today's desktop processor. cheers, -Len - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
