Messages in this thread | | | Date | Thu, 26 Aug 2010 21:56:45 +0900 | Subject | RE: [PATCH 8/9] dspbridge: add map support for big buffers | From | FUJITA Tomonori <> |
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On Thu, 26 Aug 2010 07:38:26 -0500 "Guzman Lugo, Fernando" <fernando.lugo@ti.com> wrote:
> >> due to a restriction in scatter gather lists, it can > >> not be created a list for a buffer bigger than 1MB. > >> This patch is spliting big mappings into 1MB mappings. > > > >I don't read the whole thread but the above description is incorrect. > > > >Why can't you use scatter gather chaining? You can create a scatter > >list for a buffer larger than 1MB. > > The thing is that ARM architecture does not support SG chaining. This patch should be > seen like a workaround until it is fixed in iovmm module.
Fix iovmm module is easier than the workaround?
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?
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