10/04/2005 07:30 AM, Benjamin Herrenschmidt wrote/a écrit:
iMac G5 and latest single CPU desktop G5 (SMU based machines) have a
970FX DD3 CPU that supports frequency & vooltage switching. This patch
adds support for simple dual frequency switch. It is required for the
upcoming thermal control patch for these machines.
Hello,
I know only very little about cpufreq, probably you could post your
patch to the cpufreq mailing list for better review :
[email protected] (you may have to subscride before posting,
don't remember).
For what have seen, your patch looks pretty good in general. However, is
this kind of CPU only in one CPU machines? Your patch doesn't seem
support SMP, then it's probably safer to prevent compilation on an SMP
kernel in the Makefile? Or you can add SMP support (shouldn't be so hard
in theory, but with no hardware to test it might be pointless), you can
have a look at other drivers that support it, like in
arch/i386/kernel/cpu/cpufreq/p4-clockmod.c .
Just a little more thing, concerning:
+ policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
Could you have a look if you could find the real info about how long it
takes to change the speed (put the worse case latency)? Maybe the info
can be found in some parts of the ROM you read? I don't know if
conservative or ondemand governors are supposed to be able to mix with
your code (especially wrt Windfarm) but not putting this info will
prevent them from ever working...
Cheers,
Eric
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