From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from oss.sgi.com (localhost [127.0.0.1]) by oss.sgi.com (8.12.3/8.12.3) with ESMTP id g56Hf9nC007483 for ; Thu, 6 Jun 2002 10:41:09 -0700 Received: (from majordomo@localhost) by oss.sgi.com (8.12.3/8.12.3/Submit) id g56Hf9Iu007482 for linux-mips-outgoing; Thu, 6 Jun 2002 10:41:09 -0700 X-Authentication-Warning: oss.sgi.com: majordomo set sender to owner-linux-mips@oss.sgi.com using -f Received: from ayrnetworks.com (earth.ayrnetworks.com [64.166.72.139]) by oss.sgi.com (8.12.3/8.12.3) with SMTP id g56Hf5nC007479 for ; Thu, 6 Jun 2002 10:41:06 -0700 Received: from ayrnetworks.com ([64.166.72.142]) by ayrnetworks.com (8.11.6/8.11.2) with ESMTP id g56Hh2o02940; Thu, 6 Jun 2002 10:43:02 -0700 Received: (from wjhun@localhost) by ayrnetworks.com (8.11.2/8.11.2) id g56Hebq11998; Thu, 6 Jun 2002 10:40:37 -0700 Date: Thu, 6 Jun 2002 10:40:37 -0700 From: William Jhun To: "David S. Miller" Cc: "linux-kernel@vger.kernel.org"@ayrnetworks.com, "linux-mips@oss.sgi.com"@ayrnetworks.com Subject: Re: Deprecate pci_dma_sync_{single,sg}()? Message-ID: <20020606104036.A11943@ayrnetworks.com> References: <20020605131231.B10773@ayrnetworks.com> <20020605.154747.58455261.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20020605.154747.58455261.davem@redhat.com>; from davem@redhat.com on Wed, Jun 05, 2002 at 03:47:47PM -0700 Sender: owner-linux-mips@oss.sgi.com Precedence: bulk On Wed, Jun 05, 2002 at 03:47:47PM -0700, David S. Miller wrote: > From: William Jhun > Date: Wed, 5 Jun 2002 13:12:31 -0700 > > In the current linux-mips implementation, this has some subtle problems: > pci_unmap_{single,sg}() is essentially a no-op. > > Right, I see the problem. I'll think about this some more. > > As it stands now, I think the correct solution is to require > pci_dma_prep_single() before giving the buffer back to the > device after the read. Right, that's what I was thinking. Is it asking a lot to demand that all existing drivers that use this interface add pci_dma_prep_single()? How will backward compatiblility with older drivers work? That's why I suggested leaving pci_dma_sync_single() and adding pci_dma_release_single() which can leave the cache flush to pci_dma_prep_single(). It seems like elsewhere, like the D-cache flushing interface (for virtual aliasing), both old and new interfaces co-exist. Does this seem to work out O.K. in your experience? Will