>> >> + if (target_freq <=
>> >(ioread32(&pcch_hdr->minimum_frequency) * 1000)) {
>> >> + target_freq =
>> >ioread32(&pcch_hdr->minimum_frequency) * 1000;
>> >> + dprintk("target: target_freq for cpu %d was
>> >below limit, "
>> >> + "converted it to %d\n", cpu, target_freq);
>> >> + }
>> >
>> >why not do this in the _verify() step? Does
>pcch_hdr->minimum_frequency
>> >even change "on the fly"?
>>
>> pcch_hdr->minimum_frequency does not change "on the fly".
>Also, there is no
>> need for those IO accesses:
>
>target_freq cannot be below policy->min or above policy->max.
>If it were,
>the whole cpufreq subsystem is broken. So there's no need for
>these checks,
>AFAICS.
>
I think the "ondemand" governor can ask for a target frequency that is
below policy->min.
Let's say that at a given snapshot, the frequency of a CPU is policy->cur.
At the next sampling, if the "load" on the CPU drops to a level that
satisifies the equation below, then freq_next requested by "ondemand"
will be below policy->min:
load < (threshold - differential) * policy->min / policy->cur
A patch such as below may be needed to sanitize the target frequency
requested by "ondemand". The "conservative" governor already has this check:
# diff -bur ./drivers/cpufreq/cpufreq_ondemand.c.orig ./drivers/cpufreq/cpufreq_ondemand.c
--- ./drivers/cpufreq/cpufreq_ondemand.c.orig 2009-12-11 15:06:02.000000000 -0600
+++ ./drivers/cpufreq/cpufreq_ondemand.c 2009-12-15 20:27:57.000000000 -0600
@@ -554,6 +554,9 @@
(dbs_tuners_ins.up_threshold -
dbs_tuners_ins.down_differential);
+ if (freq_next < policy->min)
+ freq_next = policy->min;
+
if (!dbs_tuners_ins.powersave_bias) {
__cpufreq_driver_target(policy, freq_next,
CPUFREQ_RELATION_L);
- naga -
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