[v4 PATCH 0/5]: cpuidle/POWER (REDISIGN): Introducing cpuidle toPOWER.

From: Arun R Bharadwaj
Date: Tue Sep 01 2009 - 07:37:27 EST


******** This is an RFC, not for inclusion **********

This patchset introduces cpuidle infrastructure to POWER, prototyping
for pseries and currently in the process of porting to x86 and hence
will *not* build on x86/other POWER platforms.

This is to get initial comments on the redesign of my earlier implementation
which can be found at http://lkml.org/lkml/2009/8/27/124

Major changes from last iteration:

* Cleanup drivers/cpuidle/cpuidle.c
Currently, the cpuidle implementation has weakness in the
framework where an exported pm_idle function pointer is
manipulated by various subsystem. The proposed framework has
a registration architecture to cleanly add and remove new idle
routines from different subsystems.

* Introduce [un]register_idle_function() routines
Implement a LIFO based approach for registering architecture
dependent idle routines.

* Sample implementation of register_idle_function for pSeries


* Extend this prototype to cover x86 and other archs that use cpuidle.
Currently, in x86, the cpu_idle() idle loop doesn't have a
default idle loop to fall back to if pm_idle is NULL, unlike
the corresponding implementation in pseries, where
ppc_md.power_save can be NULL and there is a fallback.
So we need to create a similar fork in cpu_idle() idle loop of

Patches included in this series:

1/5 - Cleanup drivers/cpuidle/cpuidle.c
2/5 - Implement routines to register and unregister idle function.
3/5 - Incorporate registering of idle loop for pSeries.
4/5 - Add Kconfig entry to enable cpuidle for POWER.
5/5 - Implement pSeries processor idle module.

Any comments on the design is welcome.

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