Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755574Ab0BPMcQ (ORCPT ); Tue, 16 Feb 2010 07:32:16 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:49786 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751946Ab0BPMcO (ORCPT ); Tue, 16 Feb 2010 07:32:14 -0500 Date: Tue, 16 Feb 2010 12:31:41 +0000 From: Alan Cox To: Nameer Yarkon Cc: linux-kernel@vger.kernel.org Subject: Re: Reading /dev/mem by dd Message-ID: <20100216123141.6c601dfd@lxorguk.ukuu.org.uk> In-Reply-To: References: X-Mailer: Claws Mail 3.7.4 (GTK+ 2.18.6; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 579 Lines: 15 > how does X11 get now direct access to the physical memory (instead of > /dev/mem) ? Via frame buffer devices. If you think about things like hot-plug it's rather hard to do frame buffer access any other way. The rules on memory types and aliasing also make it nearly impossible to do properly with /dev/mem on a modern CPU. Alan -- 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/