linux-kernel - Re: [Fdutils] DMA cache consistency bug introduced in 2.6.28

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Message-ID: <4B391B0A.2040906@cfl.rr.com>
Date:	Mon, 28 Dec 2009 15:54:34 -0500
From:	Mark Hounschell <dmarkh@....rr.com>
To:	Pavel Machek <pavel@....cz>
CC:	Andi Kleen <andi@...stfloor.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Mark Hounschell <markh@...pro.net>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>,
	Alain Knaff <alain@...ff.lu>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"fdutils@...tils.linux.lu" <fdutils@...tils.linux.lu>,
	"Li, Shaohua" <shaohua.li@...el.com>, Ingo Molnar <mingo@...e.hu>
Subject: Re: [Fdutils] DMA cache consistency bug introduced in 2.6.28

On 12/27/2009 06:09 AM, Pavel Machek wrote:
> 
>>>> This might suggest that Mark's floppy controller doesn't like
>>>> deep C? Mark, did you try booting with processor.max_cstate=1
>>>> and HPET enabled?
>>>
>>> We have indeed had historical issues with floppy and sleep states before. 
>>
>> I removed that code when moving to 64bit (floppy driver disabling C1),
>> but perhaps we need some variant of it again (but it's the first such
>> report in many years). Although it would be sad to have it again on all 
>> systems.
> 
> C1 is hlt. Are you sure? I could see how C3 could cause problems (DMA
>  latency), but...
> 
> Can mark simply try with idle=poll?
> 
> 									Pavel
> 

The floppy still fails with idle=poll

Mark
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