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RFC powernow-k7. Recalibrate cpu_khz

Bruno Ducrot cpufreq 1 version In review

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  1. v1 RFC Latest2 patches 3 repliesIn review

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#Subject and filesSizeRepliesApplied
1/2powernow-k7. Recalibrate cpu_khz (common code)arch/i386/kernel/timers/common.c include/asm-i386/timer.h+14 -20 replies
2/2powernow-k7. Recalibrate cpu_khz.arch/i386/kernel/cpu/cpufreq/powernow-k7.c+7 -20 replies

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Cover letter [PATCH] [RFC] [0/2] powernow-k7. Recalibrate cpu_khz

Hi,

Here come two patches in order to fix some issues with powernow-k7.

The main trouble is that we can't rely on cpu_khz when that one is computed at boot time. AMD will require that the CPU will be at max frequencies, but some BIOS do not respect this. More, the BIOS is only required to change the frequency of the processor, but only at POST time. Some BIOS also do not follow this rule, so that even if the processor is at full speed at POST, it may decide (probably after switching to ACPI or APM mode?) to switch to another frequency.

The only workaround for this two kind of bugs I see is to recalibrate cpu_khz, but this require discussions with other people, I guess. The second patch will be the powernow-k7 portion.

Cheers,

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Bruno Ducrot

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