Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762555AbWLKF43 (ORCPT ); Mon, 11 Dec 2006 00:56:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762556AbWLKF43 (ORCPT ); Mon, 11 Dec 2006 00:56:29 -0500 Received: from colo.lackof.org ([198.49.126.79]:59052 "EHLO colo.lackof.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762552AbWLKF42 (ORCPT ); Mon, 11 Dec 2006 00:56:28 -0500 Date: Sun, 10 Dec 2006 22:56:26 -0700 From: Grant Grundler To: Benjamin Herrenschmidt Cc: Stephen Hemminger , Greg Kroah-Hartman , linux-pci@atrey.karlin.mff.cuni.cz, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/6] MTHCA driver (infiniband) use new pci interfaces Message-ID: <20061211055626.GA527@colo.lackof.org> References: <20061208182241.786324000@osdl.org> <20061208182500.611327000@osdl.org> <1165809339.7260.19.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1165809339.7260.19.camel@localhost.localdomain> X-Home-Page: http://www.parisc-linux.org/ User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1537 Lines: 34 On Mon, Dec 11, 2006 at 02:55:39PM +1100, Benjamin Herrenschmidt wrote: > On Fri, 2006-12-08 at 10:22 -0800, Stephen Hemminger wrote: > > plain text document attachment (mthca-rbc.patch) > > Use new pci interfaces to set read request tuning values > > Untested because of lack of hardware. Sorry...I missed that. I have mthca HW on publicly available IA64 machines. I'll contact Steve off list to check if he is interested/time. > I'm worried by this... At no point do you check the host bridge > capabilities, and thus will happily set the max read req size to some > value larger than the max the host bridge can cope... > > I've been having exactly that problem on a number of setups, for > example, the sky2 cards tend to start with a value of 512 while the G5's > host bridge can't cope with more than 256 (iirc). The firmware fixes > that up properly on the G5 at least (but not on all machines), but if > you allow drivers to go tweak the value without a way to go check what > are the host bridge capabilities, you are toast. > > Of course, on PCI-X, this is moot, there is no clear definition on how > to get to a host bridge config space (if any) ... > So for PCI-X, if we want tat, we need a pcibios hook for the platform > to validate the size requested. Yes, agreed. grant - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/