[PATCH V3] cpuidle: Handle tick_broadcast_enter() failure gracefully

[Sudeep Holla]

On 08/05/15 08:35, Preeti U Murthy wrote:
> When a CPU has to enter an idle state where tick stops, it makes a call
> to tick_broadcast_enter(). The call will fail if this CPU is the
> broadcast CPU. Today, under such a circumstance, the arch cpuidle code
> handles this CPU.  This is not convincing because not only do we not
> know what the arch cpuidle code does, but we also do not account for the
> idle state residency time and usage of such a CPU.
>
> This scenario can be handled better by simply choosing an idle state
> where in ticks do not stop. To accommodate this change move the setting
> of runqueue idle state from the core to the cpuidle driver, else the
> rq->idle_state will be set wrong.
>
> Signed-off-by: Preeti U Murthy <preeti at linux.vnet.ibm.com>

I gave it a spin on ARM64 Juno platform with one of the CPU in broadcast
mode and Vexpress TC2 with broadcast timer. I found no issues in both
the cases. So, you can add:

Tested-by: Sudeep Holla <sudeep.holla at arm.com>

Regards,
Sudeep