RE: [PATCH] thermal: Add missing cpumask_clear

[Jonghwan Choi <jhbird.choi@samsung.com>]

On Fri, Jul 4, 2014 at 8:23 PM, Sachin Kamat <spk.linux@gmail.com> wrote:

> > Cpumasks should be cleared before using.
> 
> Please explain why and what is issue observed without this.
>

-> When I checked the mask value, I knew that unwanted bit is set.

Test code without cpumask_clear.

+       cpumask_set_cpu(0, &mask_val);
+       cpulist_scnprintf(buf, 64, &mask_val);
+       printk("--ID [ %d] = %s \n", id, buf);
+       th_zone->cool_dev[id] = cpufreq_cooling_register(&mask_val);


Console message-> 4.861157] [c6] --ID [ 1] = 0,4-5,7 (4,5,7 cpu bit was set.)

And when I tried to register two cooling devices with cpumask_set_cpu(0, &mask_val) and cpumask_set_cpu(4, &mask_val). 

I found that cpu 0 bit is also set in latter cpumask. (I hope latter cpumask has a cpu 4 bit.)

So I think that cpumask_clear should be inserted.

Thanks.