linux-kernel - Re: [PATCH 0/3] idle, Honor Hardware Disabled States

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Message-ID: <CAJvTdKmi2pfE+fn5-MVd8T5_0j+EbASJ992AYmVKG2osk762yQ@mail.gmail.com>
Date:	Thu, 24 Mar 2016 17:54:05 -0400
From:	Len Brown <lenb@...nel.org>
To:	Prarit Bhargava <prarit@...hat.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	X86 ML <x86@...nel.org>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>,
	Borislav Petkov <bp@...e.de>, Andi Kleen <ak@...ux.intel.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Dasaratharaman Chandramouli 
	<dasaratharaman.chandramouli@...el.com>,
	Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 0/3] idle, Honor Hardware Disabled States

On Wed, Mar 23, 2016 at 7:50 PM, Prarit Bhargava <prarit@...hat.com> wrote:
>
>
> On 03/23/2016 04:05 PM, Len Brown wrote:
>> This patch assumes that if a package state is disabled,
>> the corresponding core state must be disabled.
>> That assumption is false.
>> Indeed, that is a very popular and useful configuration.
>>
>> But even if that were not the case, this software is not necessary,
>> since the hardware handles demotion "c-state clipping" automatically.
>>
>> Yes, there is a case where a certain version of a certain processor
>> has broken demotion, but this isn't the right fix for that.
>> The right fix for that is here:
>>
>> https://bugzilla.kernel.org/show_bug.cgi?id=109081
>
> Len, should I rebase on top of this?  Would that work for you?


I guess I wasn't clear.
I don't see the benefit of your patch.
Please explain it to me.

thanks,
-Len