linux-kernel - Re: [PATCH] cpuidle: fix new C-states not functional after AC disconnect

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Message-ID: <50F2C79E.5000302@linaro.org>
Date:	Sun, 13 Jan 2013 15:41:34 +0100
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Thomas Schlichter <thomas.schlichter@....de>
CC:	Len Brown <lenb@...nel.org>, "Rafael J. Wysocki" <rjw@...k.pl>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter De Schrijver <pdeschrijver@...dia.com>,
	Andreas Müller 
	<goo@...pelspeicher.org>, Julius Werner <jwerner@...omium.org>,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpuidle: fix new C-states not functional after AC disconnect

On 01/13/2013 01:34 PM, Thomas Schlichter wrote:
> Hi,
> 
> there is a long-standing regression about new C-states not working after 
> disconnecting AC power from a laptop if the cpuidle driver "acpi-idle" is 
> used. It was reported here:
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=42870  (March 5th 2012)
> [2] https://bugzilla.kernel.org/show_bug.cgi?id=43349  (June 7th 2012)
> [3] https://lkml.org/lkml/2012/10/16/518   (October 19th 2012)
> 
> In [1] Andreas proposed a patch that initialized the missing power_usage 
> values from within acpi_idle in the same way as cpuidle does.
> In [2] I proposed a patch to use the power values provided by ACPI to 
> initialize the power_usage variables.
> In [3] Julius proposed a patch to call the initialization function 
> set_power_states()  not only once, but always when the C-states change.
> 
> Currently, Daniel Lezcano seems to be working on an intrusive change of not 
> using the power_usage value at all for choosing a C-state:
> 
> [4] https://lkml.org/lkml/2012/12/14/155
> 
> As I could not find any of these patches in any git trees to be merged for 
> 3.8, I propose an other, least intrusive patch for the time being. It is 
> attached an initializes _all_ power_usage values in the first place.
> 
> As this is a real power consumption regression since 3.2, I really ask you to 
> apply anything and push it to stable, too!

Rafael, is possible to apply the patch [1/2] I previously sent ?

https://patchwork.kernel.org/patch/1878691/

So we get this bug fixed.

I will resend the patch [2/2] as soon as possible.

  -- Daniel


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