linux-kernel - Re: [PATCH 02/02] clocksource: Start CMT at clocksource resume

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Message-ID: <aec7e5c30911300319i115efdb6p215984377cb97f22@mail.gmail.com>
Date:	Mon, 30 Nov 2009 20:19:36 +0900
From:	Magnus Damm <magnus.damm@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	linux-sh@...r.kernel.org, johnstul@...ibm.com, lethal@...ux-sh.org
Subject: Re: [PATCH 02/02] clocksource: Start CMT at clocksource resume

Hi Thomas,

On Sat, Nov 28, 2009 at 11:00 PM, Thomas Gleixner <tglx@...utronix.de> wrote:
> On Wed, 25 Nov 2009, Magnus Damm wrote:
>
>> From: Magnus Damm <damm@...nsource.se>
>>
>> Add code to start the CMT timer on clocksource resume.
>>
>> This makes sure the timer is started during sysdev_resume().
>> Without this patch the clocksource may be read as suspended,
>> this after sysdev resume but before platform device resume.
>
> Hmm, don't you have the same situation on suspend ?
>
> platform device suspend stops the clock, but the generic code expects
> it to be running until sysdev shutdown.

You are correct, the same situation exists on suspend.

> Another thing is that you now run both, the sysdev and the platform
> resume. Is that by design or accident ?

By incorrect design. =)

To fix this properly I was thinking of adding a clocksource suspend()
callback and ditch the platform ops all together. If you don't mind
then I'll post a patch for that tomorrow!

Thank you!

/ magnus
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