From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: [PATCH] [29/82] x86_64: Rename IOMMU option, fix help and mark option embedded. Date: Sun, 25 Jun 2006 15:00:54 -0400 Message-ID: <20060625190054.GA6570@devserv.devel.redhat.com> References: <449C852C.mailCZT11F9YB@suse.de> <20060624231433.GA24862@devserv.devel.redhat.com> <200606251722.23294.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([66.187.233.31]:44425 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S965319AbWFYTBM (ORCPT ); Sun, 25 Jun 2006 15:01:12 -0400 Content-Disposition: inline In-Reply-To: <200606251722.23294.ak@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Andi Kleen Cc: Alan Cox , torvalds@osdl.org, discuss@x86-64.org, akpm@osdl.org, markh@osdl.org, linux-scsi@vger.kernel.org, axboe@suse.de On Sun, Jun 25, 2006 at 05:22:23PM +0200, Andi Kleen wrote: > > Older aacraid hardware cannot address the 3-4GB range where the iommu > > remaps pages. As the PCI DMA implementation for the x86-64 is flawed and > > doesn't support any nice way to deal with this via swiotlb instead the > > driver handles it internally. > > Then you should just force a low bounce pfn < 0xfffffff for the block device - > then the block layer should use GFP_DMA bouncing. >>From a tiny 16MB DMA pool that can't sustain the required load ? Or has that bit changed. Alan