Message-ID: <1370652132.4432.68.camel@ymzhang.sh.intel.com>
Subject: Re: [PATCH 0/2] Run callback of device_prepare/complete consistently
From: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Reply-To: yanmin_zhang@linux.intel.com
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: shuox.liu@intel.com, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, pavel@ucw.cz, len.brown@intel.com,
        gregkh@linuxfoundation.org
Date: Sat, 08 Jun 2013 08:42:12 +0800
In-Reply-To: <2482951.doztFClhed@vostro.rjw.lan>
References: <1370593232-3602-1-git-send-email-shuox.liu@intel.com>
	 <2482951.doztFClhed@vostro.rjw.lan>
Organization: Intel.
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On Fri, 2013-06-07 at 12:36 +0200, Rafael J. Wysocki wrote:
> On Friday, June 07, 2013 04:20:30 PM shuox.liu@intel.com wrote:
> > dpm_run_callback is used in other stages of power states changing.
> > It provides debug info message and time measurement when call these
> > callback. We also want to benefit ->prepare and ->complete.
> > 
> > [PATCH 1/2] PM: use dpm_run_callback in device_prepare
> > [PATCH 2/2] PM: add dpm_run_callback_void and use it in device_complete
> 
> Is this an "Oh, why don't we do that?" series, or is it useful for anything
> in practice?  I'm asking, because we haven't added that stuff to start with
> since we didn't see why it would be useful to anyone.
> 
> And while patch [1/2] reduces the code size (by 1 line), so I can see some
> (tiny) benefit from applying it, patch [2/2] adds more code and is there any
> paractical reason?
Sometimes, suspend-to-ram path spends too much time (either suspend slowly
or wakeup slowly) and we need optimize it.
With the 2 patches, we could collect initcall_debug printk info and manually
check what prepare/complete callbacks consume too much time.

Thanks,
Yanmin


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