Messages in this thread | | | Date | Sun, 14 Mar 2004 16:11:00 +0100 | From | Bjoern Schmidt <> | Subject | [BUG] Re: fsb of older cpu |
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Hello Len,
i think that the fadt of my laptop is buggy, but i am not sure. The fadt tells a C2 latency of 100 and a C3 latency of 300. C3 is disabled in drivers/acpi/processor.c because type-f DMA is set.
C2 is enabled and seems to be used, but has no effects on pm. Thottling seems to have no effects too. The temperature of the cpu rises fast until one of the active or S-state trip-points is reached, in the worst case the systems goes to S5.
Now i have set the C2 valid flag statically to "0" in the sources (driver/acpi/processor.c). cat /proc/acpi/processor/.../info tells that pm is not supported anymore, and throttling seems to work now. The temperature of the cpu settled down to the aimed trip-point of 58 dC.
Can you comfirm that this behaviour is a result of a buggy fadt, or could it be that there is a bug in the kernels acpi?
Do you know if a PII Deschutes is C2 capable? In the acpi specification i can see that the programming model for c2 state is "Fixed Hardware Control Logic" which is integrated into the external chipset. Is the chipset the only dependency for c2-state, or is the processor a dependency too? I think so, of course, but its not clearly enough for me...
Greetings Bjoern Schmidt
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