linux-kernel - Re: [PATCH] x86, suspend: Save/restore THERM

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Date:	Tue, 18 Aug 2015 10:23:40 +0800
From:	Yu Chen <yu.c.chen@...el.com>
To:	Pavel Machek <pavel@....cz>, Ingo Molnar <mingo@...nel.org>
CC:	rjw@...ysocki.net, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, rui.zhang@...el.com, x86@...nel.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86, suspend: Save/restore THERM_CONTROL register for
 suspend

Hi Pavel, thanks for your review,
On 08/17/2015 09:27 PM, Pavel Machek wrote:
> On Mon 2015-08-17 12:11:15, Ingo Molnar wrote:
>>
>> * Chen Yu <yu.c.chen@...el.com> wrote:
>>
>>> A bug is reported(https://bugzilla.redhat.com/show_bug.cgi?id=1227208)
>
> Access denied :-(
>
Might need to register for accessing.
>
> What HW is this on?
>
Intel Braswell and Broadwell, detail for Broadwell:
Platform: MayanCity
Processor: 2x BROADWELL BDX_EP A0 QHPR
Chipset: Wellsburg B1 QR7E

>
> - So BIOS expects to control MSR_IA32_THERM_CONTROL . Now you suspend
>    in hot enironment but resume in cool one. BIOS sets up
>    MSR_IA32_THERM_CONTROL the right way, but you override it.
>
>    As BIOS expects to control MSR_IA32_THERM_CONTROL and machine is
>    kept cool, BIOS will not write new value to it, and machine will
>    keep running slowly.
>
Sorry, I can not quite catch up, do you mean we should let
  BIOS modifying MSR_IA32_THERM_CONTROL and  leverage linux
to adjust this value at runtime(after S3)?

> Doing this unconditionally is asking for trouble. Blacklist entry with
> affected BIOS info might be acceptable, but...
> 									Pavel
>
you mean a quirk here(accroding to dmi info ,etc)?


Best Regards,
Yu

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