From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <5.1.0.14.2.20020613184104.026b9910@pop.prodigy.net> Date: Thu, 13 Jun 2002 18:57:45 -0700 To: David Gibson From: Eugene Surovegin Subject: Re: [PATCH] pci_alloc_consistent in an interrupt context Cc: Tom Rini , Dan Malek , linuxppc-embedded@lists.linuxppc.org In-Reply-To: <20020614013352.GF26146@zax> References: <5.1.0.14.2.20020613180327.02e11f68@pop.prodigy.net> <20020613215635.GB13541@opus.bloom.county> <5.1.0.14.2.20020613122317.02e34480@mail.zultys.com> <20020613205824.GX13541@opus.bloom.county> <3D0912F4.4020300@embeddededge.com> <20020613215635.GB13541@opus.bloom.county> <5.1.0.14.2.20020613180327.02e11f68@pop.prodigy.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: At 06:33 PM 6/13/2002, David Gibson wrote: >On Thu, Jun 13, 2002 at 06:25:11PM -0700, Eugene Surovegin wrote: > > > > At 05:24 PM 6/13/2002, David Gibson wrote: > > >That's right. But I think the patch below is a better fix for the > > >problem. It makes consistent_alloc()/consistent_free() just do the > > >right thing for both cache coherent and cache non-coherent processors, > > >so we can get rid of the ifdef in pci_alloc_consistent() and > > >pci_free_consistent(). > > > > So, kmalloc will allocate non-cacheable memory? > > > > I seriously doubt it (actually I've just tested it:). > >No, but on cache coherent processors we don't need non-cacheable >memory. That's the whole point. Likewise with __get_free_pages() >which is what pci_alloc_consistent() uses on cache-coherent processors >now. OK, I got it :) One problem though, kmalloc allocated memory will not be necessarily properly aligned as required by DMA-mappings.txt Some PCI drivers may break because of this. Eugene. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/