From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 12 Dec 2002 12:26:52 +0000 (GMT) Received: from p508B7BBE.dip.t-dialin.net ([80.139.123.190]:43691 "EHLO dea.linux-mips.net") by linux-mips.org with ESMTP id ; Thu, 12 Dec 2002 12:26:51 +0000 Received: (from ralf@localhost) by dea.linux-mips.net (8.11.6/8.11.6) id gBCCKMh05834; Thu, 12 Dec 2002 13:20:22 +0100 Date: Thu, 12 Dec 2002 13:20:22 +0100 From: Ralf Baechle To: Alan Cox Cc: Vivien Chappelier , linux-mips@linux-mips.org, Ilya Volynets Subject: Re: [PATCH 2.5] SGI O2 framebuffer driver Message-ID: <20021212132022.A5060@linux-mips.org> References: <1039656676.18587.63.camel@irongate.swansea.linux.org.uk> <20021212033307.C22987@linux-mips.org> <1039697045.21231.13.camel@irongate.swansea.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <1039697045.21231.13.camel@irongate.swansea.linux.org.uk>; from alan@lxorguk.ukuu.org.uk on Thu, Dec 12, 2002 at 12:44:05PM +0000 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 884 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Thu, Dec 12, 2002 at 12:44:05PM +0000, Alan Cox wrote: > > The O2 is non-cache coherent. So with the fairly large write-back second > > level caches enabled frame buffer write could potencially be delayed > > indefinately but in any case quite long. Frame buffers are usually only > > You can flush the frame buffer pages that were touched at the end of an > operation though Flushes are very expensive operations, on the order of 16 cycles per cacheline plus memory delay. So why using them when just using the right cache mode does the right thing already. Ralf