From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Tue, 10 Jun 2003 17:36:57 +0000 Subject: Re: [Linux-ia64] heads up: i/o mmu related changes Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Tue, 10 Jun 2003 01:07:18 -0700, David Mosberger said: David> I justed checked in a changeset David> (davidm@tiger.hpl.hp.com|ChangeSet|20030610070955|57077) to David> make the kernel work better for machines with I/O MMU. This David> should fix the long-standing bug where IDE disks on machines David> with memory above 4GB would MCA if the machine has an I/O David> MMU. David> The trick was to make PCI_DMA_BUS_IS_PHYS a variable which is David> set at runtime. Machines with I/O MMUs or machines with PCI David> buses which live in separate address spaces MUST clear this David> variable. I updated the code for the zx1 I/O MMU. I didn't David> touch the SGI I/O MMU code, though, as I wouldn't be able to David> test it. Actually, you may want to hold off on this one. I think I'll need to fine-tune this a bit more. My current thinking is that we need a variable ia64_max_iommu_page_size or something like that, which will tell us what to set BIO_VMERGE_BOUNDARY to. --david