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Date: Sun, 15 Dec 2013 08:21:36 +1100
From: Nigel Cunningham <nigel@nigelcunningham.com.au>
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To: Tejun Heo <tj@kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
CC: Jens Axboe <axboe@kernel.dk>, tomaz.solc@tablix.org, aaron.lu@intel.com,
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        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [PATCH] libata, freezer: avoid block device removal while system
 is frozen
References: <20131213174932.GA27070@htj.dyndns.org> <20131213185237.GD27070@htj.dyndns.org> <20131213204034.GE27070@htj.dyndns.org> <52AB8E27.90308@nigelcunningham.com.au> <20131213230744.GA17954@htj.dyndns.org> <52AB9509.1080004@nigelcunningham.com.au> <20131214203121.GB4020@htj.dyndns.org> <20131214203652.GC4020@htj.dyndns.org>
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Hi.

On 15/12/13 07:36, Tejun Heo wrote:
> On Sat, Dec 14, 2013 at 03:31:21PM -0500, Tejun Heo wrote:
>> So, all this is about hibernation?  Does that mean that it's safe to
>> unfreeze before invoking resume?  ie. we currently do,
>>
>> 	freeze
>> 	suspend devs
>> 	resume devs
>> 	unfreeze
>>
>> If we can just do,
>>
>> 	freeze
>> 	suspend devs
>> 	unfreeze
>> 	resume devs
> Ummm... even better, does that mean, in the long term, we can decouple
> freezing and device pm operations?  If this is just about hibernation,
> there's no reason to wrap device driver pm ops with freezer, right?
>
> Thanks.
>
Rafael has spent far more time than me thinking about the semantics 
here, so I'd like to defer to him. Rafael?...

Regards,

Nigel