From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id B1512DDFB4 for ; Sat, 30 Jun 2007 09:15:07 +1000 (EST) Subject: Re: PCI IO range limitation From: Benjamin Herrenschmidt To: Matt Sealey In-Reply-To: <46853CA2.2040203@genesi-usa.com> References: <46838B54.2010806@semihalf.com> <1183052634.5521.284.camel@localhost.localdomain> <46844692.1040804@genesi-usa.com> <1183075997.5521.292.camel@localhost.localdomain> <46853CA2.2040203@genesi-usa.com> Content-Type: text/plain Date: Sat, 30 Jun 2007 09:14:59 +1000 Message-Id: <1183158899.5521.377.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Marian Balakowicz List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > Define "legacy device"? What should that entail? You mean like mapping > most of those registers to the first couple of kilobytes of "IO"? Anything that hard-decodes IOs in the low ISA range yes. That includes VGA video cards. > If they're just left as their own on their own as PCI devices, why would > it matter what the window was? Because quite a few of those things hard decodes (can't be moved around, so -have- to be able to generate cycles to those low addresses to hit them) and sometimes don't even fully decode the 32 bits addresses (though that's more rare). For example, a VGA video card in text mode hard decodes both IO and Memory at the legacy VGA ranges. Ben.