Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750755AbVILLoL (ORCPT ); Mon, 12 Sep 2005 07:44:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750760AbVILLoK (ORCPT ); Mon, 12 Sep 2005 07:44:10 -0400 Received: from magic.adaptec.com ([216.52.22.17]:1766 "EHLO magic.adaptec.com") by vger.kernel.org with ESMTP id S1750755AbVILLoJ convert rfc822-to-8bit (ORCPT ); Mon, 12 Sep 2005 07:44:09 -0400 X-MimeOLE: Produced By Microsoft Exchange V6.0.6487.1 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: [1/3] Add 4GB DMA32 zone Date: Mon, 12 Sep 2005 07:44:08 -0400 Message-ID: <547AF3BD0F3F0B4CBDC379BAC7E4189F01919BC3@otce2k03.adaptec.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [1/3] Add 4GB DMA32 zone Thread-Index: AcW3hzAHLkwJVp/xRMyliTpKmG/DkQABcU+g From: "Salyzyn, Mark" To: "Andi Kleen" , "Alan Cox" Cc: , , Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1564 Lines: 37 Andi Kleen writes: >> Adaptec AACRAID is one offender > 4GB limit is really common and the oddballs like >these have to use the same workarounds (custom bounce buffer in low GFP_DMA >memory) they always did on machines with enough memory. The 2GB limit is to deal with allocation of hardware command frames (FIB) and thus only during initialization, all the adapters deliver DMA to the full address range at 'run time' and the driver does open the limit up at that point. The reason for this strangeness is the inability of the Firmware to work around the Intel ATU when doing memcpy, where the DMA engine had no such limits. > Also the aacraid is not really an big issue on x86-64 Oh really? I have throngs (a technical term) of customers that would bear witness otherwise. > because afaik nobody shipped EM64T or AMD64 machines with these beasts. Patently false. The cards with the 2GB limits (2200S) are popular sellers in the channel, the replacement (2230S) w/o the limit is ramping though ... >[Proof of it: the current sources don't seem to handle it, so it cannot be that bad ;-] The current sources do handle it, took nearly a year for the patches to propagate from the scsi-list. Meanwhile I deliver a driver to all the customers that experienced problems, while I waited ... Sincerely -- Mark Salyzyn - 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/