Re: ACPI C and P states on Conroe

From: Joe Harvell
Date: Tue Jan 30 2007 - 19:18:54 EST


Robert Hancock wrote:
Joe Harvell wrote:


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

Right.

being moved into acpi-cpufreq. But I can't get acpi-cpufreq to load in my kernel version. Also, I would have thought speedstep-ich would be

Are you sure? Are you getting error messages?


I forget what the output from modprobe said. But I had cpufreq.debug=7. Here are the logs:

Jan 29 09:10:38 [kernel] acpi-cpufreq: acpi_cpufreq_init
Jan 29 09:10:38 [kernel] acpi-cpufreq: acpi_cpufreq_early_init
Jan 29 09:10:38 [kernel] cpufreq-core: trying to register driver acpi-cpufreq
Jan 29 09:10:38 [kernel] cpufreq-core: adding CPU 0
Jan 29 09:10:38 [kernel] acpi-cpufreq: acpi_cpufreq_cpu_init
Jan 29 09:10:38 [kernel] acpi-cpufreq: Unsupported address space [127, 127]
Jan 29 09:10:38 [kernel] cpufreq-core: initialization failed
Jan 29 09:10:38 [kernel] cpufreq-core: adding CPU 1
Jan 29 09:10:38 [kernel] acpi-cpufreq: acpi_cpufreq_cpu_init
Jan 29 09:10:38 [kernel] acpi-cpufreq: Unsupported address space [127, 127]
Jan 29 09:10:38 [kernel] cpufreq-core: initialization failed
Jan 29 09:10:38 [kernel] cpufreq-core: no CPU initialized for driver acpi-cpufreq
Jan 29 09:10:38 [kernel] cpufreq-core: unregistering CPU 0
Jan 29 09:10:38 [kernel] cpufreq-core: unregistering CPU 1


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)?

The kernel will only use C2 and C3 if the motherboard exports support for it through ACPI. Most desktop boards don't, this is normally only found on laptops.

Okay. I understand the distinction between what the processor supports and what the motherboard exports via the ACPI tables. I do still want to know what C states the E6600 supports. Does anyone know? Also, I've heard the it's possible to modify the DSDT on boards to add interfaces to processor features that the board does not provide. Of course this is a dead end if E6600 doesn't support these low power states to begin with. Assuming it does, does anyone know if it's possible to get them working on the Asus P5B Deluxe?


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