From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Grundler Subject: Re: [parisc-linux] stop the buffer bouncing Date: Tue, 16 Nov 2004 11:05:25 -0700 Message-ID: <20041116180525.GF4176@colo.lackof.org> References: <20041116063733.GA27633@colo.lackof.org> <20041116150748.GI26623@parcelfarce.linux.theplanet.co.uk> <20041116160939.GB4176@colo.lackof.org> <20041116163403.GJ26623@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: parisc-linux@lists.parisc-linux.org To: Matthew Wilcox Return-Path: In-Reply-To: <20041116163403.GJ26623@parcelfarce.linux.theplanet.co.uk> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org On Tue, Nov 16, 2004 at 04:34:03PM +0000, Matthew Wilcox wrote: > On Tue, Nov 16, 2004 at 09:09:39AM -0700, Grant Grundler wrote: > > yeah...I'm probably responsible for that setting. > > It worked the best. :^/ > > The 39/40 bit or full 64-bit support don't help on parisc-linux anyway. > > Why not? 40 bits of addressing supports up to 1TB, which exceeds the > highest physical address on any PA machine I know about -- oh, but we > can't bypass the IOMMU, right? exactly. Certainly not for CCIO. On SBA, someone could try writing DVI mode support but I'm not going to. I think DVI mode adds more complexity than performance improvement. But clearly some workloads could benefit. Anything that helps avoid IO TLB thrashing is a good thing. On ZX1 (also SBA), I suppose it's possible to fully bypass using non-coherent support. But that seems like a step backwards for general use. ... > > ergo Enabling PA20 and GSC but not PCI means CCIO *MUST* be enabled. > > ergo Enabling PA20 and PCI but not GSC means SBA *MUST* be enabled. > > > > Could someone else look at Kconfig files to verify the above two > > rules are enforced? > > Ah, "depends on" doesn't mean what you think it does. It means "if > GSC isn't selected, CCIO must be N. Oh. You are right...but YKWIM. > if GSC is M, CCIO can be N or M. > if GSC is Y, CCIO can be Y, N or M." ... > The values in the table show the permitted values that SCSI_SYM53C8XX_2 > can take on. If there's only one possible answer, it doesn't even ask > the question ;-) Think of 'depends on' as 'limit to' and it might be more > clear to you. *nod* I'll have to re-read this and the original docs...but I suspected I didn't fully understand Kconfig anyway. That's contributing to why I'm "defering" it. :^) thanks, grant _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux