Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263518AbUCTTtR (ORCPT ); Sat, 20 Mar 2004 14:49:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263519AbUCTTtR (ORCPT ); Sat, 20 Mar 2004 14:49:17 -0500 Received: from 194.149.109.108.adsl.nextra.cz ([194.149.109.108]:31901 "EHLO gate2.perex.cz") by vger.kernel.org with ESMTP id S263518AbUCTTtN (ORCPT ); Sat, 20 Mar 2004 14:49:13 -0500 Date: Sat, 20 Mar 2004 20:44:44 +0100 (CET) From: Jaroslav Kysela X-X-Sender: perex@pnote.perex-int.cz To: Russell King Cc: LKML Subject: Re: can device drivers return non-ram via vm_ops->nopage? In-Reply-To: <20040320160911.B6726@flint.arm.linux.org.uk> Message-ID: References: <20040320133025.GH9009@dualathlon.random> <20040320144022.GC2045@holomorphy.com> <20040320150621.GO9009@dualathlon.random> <20040320154419.A6726@flint.arm.linux.org.uk> <20040320160911.B6726@flint.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1449 Lines: 37 On Sat, 20 Mar 2004, Russell King wrote: > It is well known that virt_to_page() is only valid on virtual addresses > which correspond to kernel direct mapped RAM pages, and undefined on > everything else. Unfortunately, ALSA has been using it with > pci_alloc_consistent() for a long time, and this behaviour is what > makes ALSA broken. The fact it works on x86 is merely incidental. It works on PPC as well (at least we have no error reports). > If ALSA wants this functionality, the ALSA people should ideally have > put their requirements forward during the 2.5 development cycle so the > problem could be addressed. Yes, I'm sorry about that, but the ->nopage usage was requested by Jeff Garzik and we're not gurus for the VM stuff. Because we're probably first starting using of this mapping scheme, it resulted to problems. > However, luckily in this instance, it is not a big problem to solve. > It just requires time to sort through all the abstraction layers upon > abstraction layers which ALSA has. > > - and I'm doing exactly this, right now. Be patient. - Thanks a lot. Jaroslav ----- Jaroslav Kysela Linux Kernel Sound Maintainer ALSA Project, SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/