From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753528Ab1AGVPJ (ORCPT ); Fri, 7 Jan 2011 16:15:09 -0500 Received: from lo.gmane.org ([80.91.229.12]:60907 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752762Ab1AGVPH (ORCPT ); Fri, 7 Jan 2011 16:15:07 -0500 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: linux-kernel@vger.kernel.org To: linux-kernel@vger.kernel.org From: Nikolaus Rath Subject: CPU Initiated DMA Date: Fri, 07 Jan 2011 15:55:29 -0500 Message-ID: <87mxncv3ge.fsf@inspiron.ap.columbia.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: ebox.rath.org Mail-Copies-To: never User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) Cancel-Lock: sha1:r8hBL4ImWY4sHtS3RZdC3jR15KY= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, I want to write a driver for a rather dumb PCI card, which cannot become bus master itself. Is it possible to use a DMA controller on the mainboard to still transfer data to the card without occupying the CPU? (I believe this is the way DMA used to work on ISA cards, but do recent x86 systems still have a DMA controller for the CPU?) Any pointers are greatly appreciated. I looked into "Linux Device Drivers", but the DMA chapter seems to be only about the device becoming busmaster. Best, -Nikolaus -- »Time flies like an arrow, fruit flies like a Banana.« PGP fingerprint: 5B93 61F8 4EA2 E279 ABF6 02CF A9AD B7F8 AE4E 425C