Re: [v7 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

On Wed, 2009-10-07 at 16:56 +0530, Vaidyanathan Srinivasan wrote:

* Peter Zijlstra [off-list ref] [2009-10-06 20:04:39]:

quoted

On Tue, 2009-10-06 at 22:05 +0530, Arun R Bharadwaj wrote:

quoted

Also, the per-cpu nature of registration/unregistration of cpuidle
has been maintained as ACPI needs this.

Right, so can't we ditch that and have acpi default to the lowest

common

quoted

C-state and warn when various cpus report different C-states?

Hi Peter,

As Arjan mentioned previously, the per-cpu registration has to stay
for x86 for now due to legacy ACPI compatibility.  Breaking that may
break lot of existing users and we do not have a clean fallback
method.  

From what I understood some broken ass bioses report different C state

availability on different CPUs in the same SMP system.

I'm suggesting to work around that by limiting all CPUs to the subset of
C states reported on all CPUs, instead of the current mess.

I haven't heard anybody tell me why that wouldn't be possible on x86