________________________________________ >From: FUJITA Tomonori [fujita.tomonori@xxxxxxxxxxxxx] >Sent: Thursday, August 26, 2010 9:03 AM >To: Guzman Lugo, Fernando >Cc: fujita.tomonori@xxxxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; ohad@xxxxxxxxxx; hiroshi.doyu@xxxxxxxxx; ameya.palande@xxxxxxxxx; >felipe.contreras@xxxxxxxxx >Subject: RE: [PATCH 8/9] dspbridge: add map support for big buffers > >On Thu, 26 Aug 2010 08:16:24 -0500 >"Guzman Lugo, Fernando" <fernando.lugo@xxxxxx> wrote: > >> >From a quick look, arch/arm/plat-omap/iovmm.c does nothing wrong about >> >scatter gather chaining. arm/arm/mm/dma-mapping.c looks fine too about >> >it. Maybe just defining ARCH_HAS_SG_CHAIN works? >> >> I can try, but it looks tricky for me. Maybe someone else can tell us why >> SG chain is not supported for ARM or if there is a problem just defining >> ARCH_HAS_SG_CHAIN. > >I suppose that nobody in ARM has been interested in the feature. It >was invented to improve I/O performance with large I/O requests. No >wonder embeded people aren't interested in it. > >fujita@rose:~/git/linux-2.6$ find arch -name 'scatterlist.h'|xargs grep HAS_SG >arch/x86/include/asm/scatterlist.h:#define ARCH_HAS_SG_CHAIN >arch/ia64/include/asm/scatterlist.h:#define ARCH_HAS_SG_CHAIN >arch/sparc/include/asm/scatterlist.h:#define ARCH_HAS_SG_CHAIN >arch/powerpc/include/asm/scatterlist.h:#define ARCH_HAS_SG_CHAIN Ok, so let me try SG chain, that should be the correct fix. Thanks a lot, Fernando. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
