From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gra-lx1.iram.es (gra-lx1.iram.es [150.214.224.41]) by ozlabs.org (Postfix) with ESMTP id A1053B70ED for ; Mon, 22 Nov 2010 21:42:35 +1100 (EST) Date: Mon, 22 Nov 2010 11:37:17 +0100 From: Gabriel Paubert To: Gary Thomas Subject: Re: Change in PCI behaviour Message-ID: <20101122103717.GA11649@iram.es> References: <4CE69AF6.6090408@mlbassoc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4CE69AF6.6090408@mlbassoc.com> Cc: Linux PPC Development List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Nov 19, 2010 at 08:42:46AM -0700, Gary Thomas wrote: > In this case, note that PCI device 0000:00:0c.0 is at 0xc0000000. > This causes problems because it's a truly stupid device that does > not work properly at PCI [relative] address 0x00000000. It simply > does not respond at that address. Pick anywhere else and it will > work fine! Yes, but it was one upon a time in the PCI spec that setting the a base register to 0 should disable the corresponding decoder. I don't know whether this has changed (I actually never had the final PCI spec, only drafts). However I once had a device who actually did not disable base addresses set to zero and this was described as a bug in its (numerous) errata. This also caused a lot of mayhem since in some versions/configurations it used up to 64kB of PCI I/O space (especially fun on x86...). Gabriel