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[CPUFREQ] powernow-k6: set transition latency value so ondemand gover…
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…nor can be used

Set the transition latency to value smaller than CPUFREQ_ETERNAL so
governors other than "performance" work (like the "ondemand" one).

The value is found in "AMD PowerNow! Technology Platform Design Guide for
Embedded Processors" dated December 2000 (AMD doc #24267A). There is the
answer to one of FAQs on page 40 which states that suggested complete transition
period is 200 us.

Tested on K6-2+ CPU with K6-3 core (model 13, stepping 4).

Signed-off-by: Krzysztof Helt <[email protected]>
Signed-off-by: Dave Jones <[email protected]>
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Krzysztof-H authored and Dave Jones committed Nov 24, 2009
1 parent b8cbe7e commit db2820d
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/x86/kernel/cpu/cpufreq/powernow-k6.c
Original file line number Diff line number Diff line change
Expand Up @@ -164,7 +164,7 @@ static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
}

/* cpuinfo and default policy values */
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
policy->cpuinfo.transition_latency = 200000;
policy->cur = busfreq * max_multiplier;

result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
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