Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 3 Oct 2001 03:19:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 3 Oct 2001 03:19:40 -0400 Received: from wiprom2mx1.wipro.com ([203.197.164.41]:18088 "EHLO wiprom2mx1.wipro.com") by vger.kernel.org with ESMTP id ; Wed, 3 Oct 2001 03:19:34 -0400 Message-ID: <3BBABC41.50203@wipro.com> Date: Wed, 03 Oct 2001 12:50:33 +0530 From: "BALBIR SINGH" User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20010913 X-Accept-Language: en-us MIME-Version: 1.0 To: linux-kernel Subject: [QUESTION] ISA overhead Content-Type: multipart/mixed; boundary="------------InterScan_NT_MIME_Boundary" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------InterScan_NT_MIME_Boundary Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit With 2.5 coming soon, something about ISA has been bothering me. All DMA has been limited to 16MB, this is ofcourse going to go away with the PCI DMA patch which allows PCI-DMA to use all the memory (4GB for 32 bit cards). All the setup of page-frames, etc is done with the knowledge of ISA. I was wondering if ISA should be treated as a special case in 2.5 and only if the ISA bus and/or ISA device is present should we do the 16MB setup. Are there other devices (like MCA) limited to doing 16 MB or so of DMA?, if so they too should be handled as a special case. I think this is the correct approach, now that all available devices are almost PCI. The default DMA space should be 32 bit, with special devices or buses like ISA being handled differently. The current code should be hidden under a #ifdef and be enabled only if CONFIG_ ISA_DMA or something similar is set. Comments, suggestions Balbir PS: Please do not worry about the attachment, I have no control over it. "Accepting criticism is the fastest way to learn the right things" - Just made it up (I am no longer scared of being flamed) --------------InterScan_NT_MIME_Boundary Content-Type: text/plain; name="Wipro_Disclaimer.txt" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="Wipro_Disclaimer.txt" ---------------------------------------------------------------------------------------------------------------------- Information transmitted by this E-MAIL is proprietary to Wipro and/or its Customers and is intended for use only by the individual or entity to which it is addressed, and may contain information that is privileged, confidential or exempt from disclosure under applicable law. If you are not the intended recipient or it appears that this mail has been forwarded to you without proper authority, you are notified that any use or dissemination of this information in any manner is strictly prohibited. In such cases, please notify us immediately at mailto:mailadmin@wipro.com and delete this mail from your records. ---------------------------------------------------------------------------------------------------------------------- --------------InterScan_NT_MIME_Boundary-- - 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/