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From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Yao Yuan <yao.yuan@freescale.com>,
        "vinod.koul@intel.com" <vinod.koul@intel.com>,
        "dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stefan@agner.ch" <stefan@agner.ch>
Subject: Re: [PATCH] dmaengine: fsl-edma: add PM suspend/resume support
Date: Wed, 15 Jul 2015 16:54:33 +0200
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On Wednesday 15 July 2015 10:29:55 Yao Yuan wrote:
> Hi Arnd,
> 
> Thanks for your review.
> And can you give me more information?
> In my opinion, The fsl_edma_pm_state will just be used when CONFIG_PM support. So why not use the #ifdefs to remove the 
> unnecessary code? Since the PM will not be selected in many use cases.

I would consider code readability more important than saving a
few instructions, and the #ifdef interrupts the reading flow.
Another aspect is that the compiler does not produce warnings
for incorrect code in an #ifdef, so we try to use e.g. 'if (IS_ENABLED(CONFIG_FOO))'
instead of '#ifdef CONFIG_FOO' wherever possible.

	Arnd