Re: [PATCH] powerpc: remove IOMMU_VMERGE config option
From: Michael Ellerman
Date: Tue Mar 02 2010 - 19:13:59 EST
On Wed, 2010-03-03 at 08:54 +0900, FUJITA Tomonori wrote:
> Seems that IOMMU_VMERGE option description gives the false
> 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.
> 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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