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 ESMTPS id 0C48EDDE0E for ; Sat, 12 Jul 2008 13:34:33 +1000 (EST) Subject: Re: [PATCH] powerpc: Fix problems with 32bit PPC's running with more than 2GB of RAM From: Benjamin Herrenschmidt To: Becky Bruce In-Reply-To: References: <1215611076-13518-1-git-send-email-sr@denx.de> <1215633758.8970.372.camel@pasglop> <20080709162219.4c07a67e@zod.rchland.ibm.com> <1215635979.8970.385.camel@pasglop> <20080709204435.4214f277@zod.rchland.ibm.com> Content-Type: text/plain Date: Sat, 12 Jul 2008 13:33:54 +1000 Message-Id: <1215833634.7549.143.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Stefan Roese Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > Are you *sure* you can see all 4GB? I thought we lost some of the 32- > bit PCI address space for PCI IO...... Disclaimer: I'm no expert on > PCI :) You are right. I didn't think that through when I replied. We do lose some of it for MMIO (not IO). So we cannot really go all the way to 4G because we can't DMA to all of it, right. > FYI, I'm *very* close to having swiotlb fully functional on powerpc to > support larger RAM - I am able to boot with 6GB on 8641 right now. > There are some bugs that I'm still shaking out - I hope to push this > out in the next couple of weeks. That won't make .27 then ? Cheers, Ben.