From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: pte_pagenr/MAP_NR deleted in pre6 Date: Thu, 17 Aug 2000 20:33:33 +0100 (BST) In-Reply-To: <200008171920.MAA23931@pizda.ninka.net> from "David S. Miller" at Aug 17, 2000 12:20:50 PM MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: From: Alan Cox Sender: owner-linux-mm@kvack.org Return-Path: To: "David S. Miller" Cc: alan@lxorguk.ukuu.org.uk, kanoj@google.engr.sgi.com, sct@redhat.com, roman@augan.com, linux-mm@kvack.org, linux-kernel@vger.rutgers.edu, rmk@arm.linux.org.uk, nico@cam.org, davidm@hpl.hp.com List-ID: > I'll probably be adding isa_virt_to_bus, because when it is in fact > "ISA like" the driver already knows that it must be certain that the isa_alloc_consistent makes sense actually. Its needed for ISA bus masters on ancient mips and other crap > physical address is below the 16MB mark right? Then the cases left on 16Mb for ISA - except on a few late 486 era boxes with magic extensions (which we'd finalyl be able to use) > x86 are MCA (which can use the ISA interface) and PCI drivers which no MCA bus is 32bit - its closer to PCI than ISA. mca_alloc_consistent is doable and if some loon ever does do old IBM power boxes it will be needed as they apparently arent cache coherent MCA > drivers. For example, BTTV still doesn't use the PCI dma stuff simply > because nobody wishes to use their brains a little bit and encapsulate > the user DMA stuff into a common spot (it's duplicated in 4 or 5 > drivers) which uses scatter gather lists with the DMA api. BTTV doesnt use it because the current stuff works and for post 2.4 using mmap_kiovec() and similar stuff probably will be a better solution - that will also help us to push PCI bug awareness into pci not drivers Also mmap_kiovec will let i810 and some other sound cards do scatter gather buffers sensibly. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux.eu.org/Linux-MM/