[PATCH 1/5] cpuidle: psci: Fail cpuidle registration if set OSI mode failed

Sudeep Holla sudeep.holla at arm.com
Fri Jun 26 10:33:55 EDT 2020

On Mon, Jun 15, 2020 at 05:20:50PM +0200, Ulf Hansson wrote:
> Currently we allow the cpuidle driver registration to succeed, even if we
> failed to enable the OSI mode when the hierarchical DT layout is used. This
> means running in a degraded mode, by using the available idle states per
> CPU, while also preventing the domain idle states.

Is that not better than not registering itself ? I tend to disagree here.

> Moving forward, this behaviour looks quite questionable to maintain, as
> complexity seems to grow around it, especially when trying to add support
> for deferred probe, for example.

I thought the sync_state in the driver must deal with that.

> Therefore, let's make the cpuidle driver registration to fail in this
> situation, thus relying on the default architectural cpuidle backend for
> WFI to be used.

CPU level states work w/o the need of OSI, and better than WFI. That was
the original aim. If that is not working, we must make it work instead
of falling back on WFI IMO.


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