From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: [irda-users] [PATCH] Make VLSI FIR depend on X86 Date: Tue, 21 Oct 2003 00:12:41 -0700 Sender: netdev-bounce@oss.sgi.com Message-ID: <20031021001241.390a16df.davem@redhat.com> References: <20031020211706.5be33474.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: lists@mdiehl.de, noah@caltech.edu, irda-users@lists.sourceforge.net, netdev@oss.sgi.com, linux-kernel@vger.kernel.org Return-path: To: Martin Diehl In-Reply-To: Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Tue, 21 Oct 2003 09:12:53 +0200 (CEST) Martin Diehl wrote: > Last time I checked pci_dma_sync was meant to sync the mapping when > ownership gets transferred from busmaster to cpu, i.e. after hardware > used/modified the buffer. What about the other direction when the cpu > filled a reused streaming map to device and wants to pass ownership to the > busmaster - we need to flush cpu caches to make sure the busmaster sees > the modified data. That's absolutely correct. Several times I've noted that this is a BUG in the API, that there is no way to sync the other way, someone just has to add the interface hooks then all the platform maintainers will implement it. Here, do this, add a new interface called pci_dma_sync_to_device() with the appropriate args. Add a NOP implementation to asm-i386/pci.h and suitable documentation changes to Documentation/DMA-mapping.txt When you send me that patch, I'll work with the platform maintainers to take care of the rest. Deal?