On Thu, May 16, 2013 at 12:19:48PM -0600, Stephen Warren wrote:
> Is there a specific reason for that; is there some problem in the core
> ARM code that implies CPU0 should never be disabled?
No. This is the code I removed:
-int tegra_cpu_disable(unsigned int cpu)
-{
- /*
- * we don't allow CPU 0 to be shutdown (it is still too special
- * e.g. clock tick interrupts)
- */
- return cpu == 0 ? -EPERM : 0;
-}
This gets called from here:
static int platform_cpu_disable(unsigned int cpu)
{
if (smp_ops.cpu_disable)
return smp_ops.cpu_disable(cpu);
/*
* By default, allow disabling all CPUs except the first one,
* since this is special on a lot of platforms, e.g. because
* of clock tick interrupts.
*/
return cpu == 0 ? -EPERM : 0;
}
Notice the useless utterly nature of tegra_cpu_disable() given that it's
doing _precisely_ the same thing as the common code. It might as well
not even exist - and it doesn't for that very reason. Never provide
implementations for methods which are copies of the default action if
no method is provided.
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