linux-kernel - Re: [PATCH] x86: usb debug port early console

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Message-ID: <4887F33D.6020803@zytor.com>
Date:	Wed, 23 Jul 2008 23:13:01 -0400
From:	"H. Peter Anvin" <hpa@...or.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Yinghai Lu <yhlu.kernel@...il.com>, mingo@...e.hu,
	tglx@...utronix.de, andi@...stfloor.org, arjan@...radead.org,
	greg@...ah.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: usb debug port early console

Eric W. Biederman wrote:
> 
>>> +static void dbgp_breath(void)
>>> +{
>>> +	/* Sleep to give the debug port a chance to breathe */
>>> +}
>> I expect the compiler will optimise away any calls to this.
> 
> It is documentation that is if it might be a good idea to not hit the
> hardware there.
> 

Sounds an awful lot like cpu_relax(); doesn't it?

	-hpa

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