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From: Michael Ellerman <michael@ellerman.id.au>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: linuxppc-dev@ozlabs.org, davem@davemloft.net,
	linux-kernel@vger.kernel.org, arnd@arndb.de,
	benh@kernel.crashing.or
Subject: Re: [PATCH] powerpc: remove IOMMU_VMERGE config option
Date: Wed, 03 Mar 2010 11:13:52 +1100	[thread overview]
Message-ID: <1267575232.7814.21.camel@concordia> (raw)
In-Reply-To: <20100303085404R.fujita.tomonori@lab.ntt.co.jp>

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On Wed, 2010-03-03 at 08:54 +0900, FUJITA Tomonori wrote:
> Seems that IOMMU_VMERGE option description gives the false
> information:
> 
> http://marc.info/?l=linux-sparc&m=126753808727669&w=2
> http://marc.info/?l=linux-sparc&m=126753880528825&w=2
> 
> IOMMU_VMERGE is unnecessary nowadays so how about removing it?

Except you didn't remove it, you just made it uneditable? Why not get
rid of it entirely.

cheers

> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 155d571..2dfa83b 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -314,17 +314,8 @@ config 8XX_MINIMAL_FPEMU
>  	  It is recommended that you build a soft-float userspace instead.
>  
>  config IOMMU_VMERGE
> -	bool "Enable IOMMU virtual merging"
> +	def_bool y
>  	depends on PPC64
> -	default y
> -	help
> -	  Cause IO segments sent to a device for DMA to be merged virtually
> -	  by the IOMMU when they happen to have been allocated contiguously.
> -	  This doesn't add pressure to the IOMMU allocator. However, some
> -	  drivers don't support getting large merged segments coming back
> -	  from *_map_sg().
> -
> -	  Most drivers don't have this problem; it is safe to say Y here.
>  
>  config IOMMU_HELPER
>  	def_bool PPC64



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  reply	other threads:[~2010-03-03  0:13 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-02 23:54 [PATCH] powerpc: remove IOMMU_VMERGE config option FUJITA Tomonori
2010-03-03  0:13 ` Michael Ellerman [this message]
2010-03-03  0:25   ` FUJITA Tomonori

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