From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1M19wW-00057o-0C for qemu-devel@nongnu.org; Mon, 04 May 2009 21:59:36 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1M19wR-00054Y-9P for qemu-devel@nongnu.org; Mon, 04 May 2009 21:59:35 -0400 Received: from [199.232.76.173] (port=35629 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1M19wR-00054V-3T for qemu-devel@nongnu.org; Mon, 04 May 2009 21:59:31 -0400 Received: from mail2.shareable.org ([80.68.89.115]:52553) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1M19wQ-0007xl-J3 for qemu-devel@nongnu.org; Mon, 04 May 2009 21:59:30 -0400 Date: Tue, 5 May 2009 02:59:28 +0100 From: Jamie Lokier Subject: Re: [Qemu-devel] [PATCH] 64 bit I/O support v7 Message-ID: <20090505015928.GE12731@shareable.org> References: <49EDB109.5010009@earthlink.net> <49FB1302.4090904@earthlink.net> <49FB88C8.9060906@earthlink.net> <200905020057.23902.paul@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Blue Swirl Cc: Robert Reif , Paul Brook , qemu-devel@nongnu.org Blue Swirl wrote: > - Small writes cause a read-modify-write cycle, but I think that may > happen with real devices too. Another solution is to write zero in > other byte lanes without reading. On PCI and I think most buses, there are separate byte-enable pins for writing each byte lane and the hardware can decide to ignore the unenabled bytes or not. -- Jamie