On Thursday 29 August 2013 06:02 AM, Viresh Kumar wrote:
> On Fri, Sep 23, 2011 at 2:37 AM, Kevin Hilman <khilman@xxxxxx> wrote:
>> From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
>>
>> On OMAP SMP configuartion, both processors share the voltage
>> and clock. So both CPUs needs to be scaled together and hence
>> needs software co-ordination.
>>
>> Also, update lpj with reference value to avoid progressive error.
>>
>> Adjust _both_ the per-cpu loops_per_jiffy and global lpj. Calibrate
>> them with with reference to the initial values to avoid a
>> progressively bigger and bigger error in the value over time.
>>
>> While at this, re-use the notifiers for UP/SMP since on UP machine or
>> UP_ON_SMP policy->cpus mask would contain only the boot CPU.
>>
>> Based on initial SMP support by Santosh Shilimkar.
>>
>> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
>> [khilman@xxxxxx: due to overlap/rework, combined original Santosh patch
>> and Russell's rework]
>> Signed-off-by: Kevin Hilman <khilman@xxxxxx>
>> ---
>> drivers/cpufreq/omap-cpufreq.c | 80 +++++++++++++++++++++++++++++++++++-----
>> 1 files changed, 70 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
>
>> + /*
>> + * On OMAP SMP configuartion, both processors share the voltage
>> + * and clock. So both CPUs needs to be scaled together and hence
>> + * needs software co-ordination. Use cpufreq affected_cpus
>> + * interface to handle this scenario. Additional is_smp() check
>> + * is to keep SMP_ON_UP build working.
>> + */
>> + if (is_smp()) {
>> + policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
>> + cpumask_or(cpumask, cpumask_of(policy->cpu), cpumask);
>> + cpumask_copy(policy->cpus, cpumask);
>> + }
>
> Does somebody remember importance of is_smp() here??
>
Above code was under #ifdef CONFIG_SMP and SMP_ON_UP where config
SMP was enabled as well above steps were not needed.
> Current code looks like:
>
> if (is_smp())
> cpumask_setall(policy->cpus);
>
> And I was looking to remove this check if it is no more useful.. And
> so simply do
>
> cpumask_setall(policy->cpus);
>
Thats should work I guess. Infact I changed this i downstream kernel
a while back but forgot to send a patch. Just see if for some reason
above can break UP machine since this driver is used on UP machines
as well. Other than that, it should be fine
Regards,
Santosh
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