From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Higdon Subject: Re: mpt sets 64bit consistent mask yet requires mapping in same 4 GB chunk?!? Date: Fri, 13 Feb 2004 15:08:09 -0800 Sender: linux-ia64-owner@vger.kernel.org Message-ID: <20040213230809.GB504054@sgi.com> References: <0E3FA95632D6D047BA649F95DAB60E5703EF915E@exa-atlanta.se.lsil.com> <20040213213043.GB20323@sgi.com> <200402131552.43935.bjorn.helgaas@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <200402131552.43935.bjorn.helgaas@hp.com> To: Bjorn Helgaas Cc: Jesse Barnes , "Moore, Eric Dean" , Alex Williamson , linux-scsi@vger.kernel.org, linux-ia64@vger.kernel.org List-Id: linux-scsi@vger.kernel.org On Fri, Feb 13, 2004 at 03:52:43PM -0700, Bjorn Helgaas wrote: > On Friday 13 February 2004 2:30 pm, Jesse Barnes wrote: > > On Fri, Feb 13, 2004 at 04:20:35PM -0500, Moore, Eric Dean wrote: > > > I added pci_set_consistent_dma_mask() per request from > > > Jeremy Higdon back on 12/03/03. He > > > was having problems on a Altix (IA64) system. See > > > attached email. What is your recommendation? I have a mpt > > > patch in the queue which doesn't address this. > > > > > > On Friday, February 13, 2004 9:12 AM, Alex Williamson wrote: > > > > These are two perfectly valid consistent mappings as far as the > > > > platform code is concerned. I think mpt really needs to either set > > > > a 32bit consistent map of do a single allocation when it requires > > > > this type of thing. Thanks, > > > > I think Alex's second suggestion would be the best--do a single > > allocation rather than falling back to a 32 bit consistent mask. > > But even with a single allocation, there's nothing to prevent it > from crossing a 4GB boundary, is there? I don't think the Linux memory allocator will give back memory that crosses a 32 bit boundary. But I'm not an expert. If I'm wrong, hopefully an expert will chime in :-) jeremy