Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751320Ab2HHEFn (ORCPT ); Wed, 8 Aug 2012 00:05:43 -0400 Received: from hqemgate03.nvidia.com ([216.228.121.140]:7744 "EHLO hqemgate03.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751032Ab2HHEFk (ORCPT ); Wed, 8 Aug 2012 00:05:40 -0400 X-PGP-Universal: processed; by hqnvupgp05.nvidia.com on Tue, 07 Aug 2012 21:05:37 -0700 Message-ID: <5021E3D8.3010503@nvidia.com> Date: Wed, 8 Aug 2012 09:28:17 +0530 From: Venu Byravarasu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 To: , , , , CC: , , Subject: What is the significance of coherent_dma_mask? Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 567 Lines: 19 Hi, Some of the USB drivers are setting coherent_dma_mask & many others are not doing it. From the description present in the comment beside this field in device.h, I could not understand its real significance. Can some one plz let me know its real need and use case where it is mandatory to use it? Thanks, Venu -- 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/