HEADSUP: cpufreq import complete, acpi_throttling changed
nate at root.org
Mon Feb 14 10:35:18 PST 2005
Kevin Oberman wrote:
>>Date: Sun, 13 Feb 2005 15:33:27 -0800
>>From: Nate Lawson <nate at root.org>
>>One person reported Cx states being broken by the cpufreq import.
>>(Well, actually he got a C3 state that he didn't have before but it
>>didn't work.) Try setting hw.acpi.cpu.cx_lowest to C1 or something
>>you're sure works.
I think I've figured that one out also. When we write PSTATE_CNT to the
SMI control register, his system decides to offer another Cx state in
addition to providing OS control over Px states. It probably is using
this as an ad-hoc way to detect that we're an advanced OS.
> Things are better now, and it was not really an ACPI issue.
> For about the millionth time I remind myself: Only change one thing at a
> At the same time that I started running cpufreq and acpi_perf, I also
> switched from 4BSD to ULE. This is why the system started running so
> much hotter!
> Throttling is now working correctly and I can keep my CPU at about 175(F)
> degrees or a kernel build by lowering the "frequency" from 1800 to
> 1350. My dmesg shows ACPI throttling setting up fine:
> cpu0: <ACPI CPU (3 Cx states)> on acpi0
> acpi_perf0: <ACPI CPU Frequency Control> on cpu0
> acpi_throttle0: <ACPI CPU Throttling> on cpu0
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