From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 487046B0012 for ; Mon, 13 Jun 2011 14:54:42 -0400 (EDT) Date: Mon, 13 Jun 2011 11:54:37 -0700 From: Jesse Barnes Subject: Re: [Linaro-mm-sig] [RFC 0/2] ARM: DMA-mapping & IOMMU integration Message-ID: <20110613115437.62824f2f@jbarnes-desktop> In-Reply-To: References: <1306308920-8602-1-git-send-email-m.szyprowski@samsung.com> <201106131707.49217.arnd@arndb.de> <20110613154033.GA29185@1n450.cable.virginmedia.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: M.K.Edwards@gmail.com Cc: KyongHo Cho , Russell King - ARM Linux , Arnd Bergmann , Catalin Marinas , Joerg Roedel , linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, Kyungmin Park , linux-arm-kernel@lists.infradead.org On Mon, 13 Jun 2011 10:55:59 -0700 "Michael K. Edwards" wrote: > As far as I can tell, there is not yet any way to get real > cache-bypassing write-combining from userland in a mainline kernel, > for x86/x86_64 or ARM. Well only if things are really broken. sysfs exposes _wc resource files to allow userland drivers to map a given PCI BAR using write combining, if the underlying platform supports it. Similarly, userland mapping of GEM objects through the GTT are supposed to be write combined, though I need to verify this (we've had trouble with it in the past). -- Jesse Barnes, Intel Open Source Technology Center -- 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-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org