Date: Sun, 2 Nov 2014 17:07:46 +0100 From: Tijl Coosemans <tijl@FreeBSD.org> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r273963 - head/sys/dev/agp Message-ID: <20141102170746.287a64e1@kalimero.tijl.coosemans.org> In-Reply-To: <54564D5C.8090100@freebsd.org> References: <201411021126.sA2BQcx4053562@svn.freebsd.org> <54564D5C.8090100@freebsd.org>
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On Sun, 02 Nov 2014 07:27:24 -0800 Nathan Whitehorn <nwhitehorn@freebsd.org> wrote: > There is actually a write-combining memory type on PowerPC. You can set > it the same way as on x86 (with VM_MEMATTR_WRITE_COMBINING). Yes, that's what the patch does, but in sys/powerpc (aim/mmu_oea.c, aim/mmu_oea64.c and booke/pmap.c) VM_MEMATTR_WRITE_COMBINING becomes PTE_I meaning Caching Inhibited. Does powerpc do write-combining for this type? That code also maps VM_MEMATTR_WRITE_BACK to PTE_I by the way. I think that should be PTE_M (write-back caching + cache coherency).
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