From mboxrd@z Thu Jan 1 00:00:00 1970 From: jbarnes@sgi.com (Jesse Barnes) Date: Tue, 10 Jun 2003 18:37:24 +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, Jun 10, 2003 at 10:36:57AM -0700, David Mosberger wrote: > >>>>> 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. Ok, the changes for sn2 look pretty straightforward. FYI, our IOMMU supports 4k and 16k pages. Thanks, Jesse