From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 14 Jun 2002 15:14:50 +1000 From: David Gibson To: Tom Rini Cc: Dan Malek , Eugene Surovegin , linuxppc-embedded@lists.linuxppc.org Subject: Re: [PATCH] pci_alloc_consistent in an interrupt context Message-ID: <20020614051450.GM26146@zax> References: <5.1.0.14.2.20020613122317.02e34480@mail.zultys.com> <20020613205824.GX13541@opus.bloom.county> <3D0912F4.4020300@embeddededge.com> <20020613215635.GB13541@opus.bloom.county> <20020614002419.GM4228@zax> <20020614003807.GD13541@opus.bloom.county> <20020614004539.GB26146@zax> <20020614005156.GE13541@opus.bloom.county> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20020614005156.GE13541@opus.bloom.county> Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: On Thu, Jun 13, 2002 at 05:51:56PM -0700, Tom Rini wrote: > > On Fri, Jun 14, 2002 at 10:45:39AM +1000, David Gibson wrote: > > On Thu, Jun 13, 2002 at 05:38:07PM -0700, Tom Rini wrote: > [snip] > > > Er, the problem of setting dma_handle twice? > > > > Well, it fixes that and as a bonus gets rid of the ifdefs in > > pci_{alloc,free}_consistent() and means that if we ever port a driver > > using consistent_{alloc,free}() to a processor that *is* cache > > coherent it will Just Work. > > In theory at that point OCP would either have its API fully flushed out > or be applied nicely on top of the generic driver work in 2.5 and it > would just work anyhow :) Well at the moment OCP drivers call consistent_alloc() directly which would always fail on cache-coherent processors. > > > My only concern is that are things still consistent on non consistent > > > procs? > > > > Absolutely - no change to the code path at all on non cache coherent > > processors. > > So kmalloc/kfree are equivilent to __get_free_pages/free_pages ? Read that again: on *non* cache coherent processors the code path is the same. kmalloc() vs. __get_free_pages() is a problem for processors which *are* cache coherent. -- David Gibson | For every complex problem there is a david@gibson.dropbear.id.au | solution which is simple, neat and | wrong. -- H.L. Mencken http://www.ozlabs.org/people/dgibson ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/