Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756593AbYAISXm (ORCPT ); Wed, 9 Jan 2008 13:23:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754659AbYAISXf (ORCPT ); Wed, 9 Jan 2008 13:23:35 -0500 Received: from smtp6.pp.htv.fi ([213.243.153.40]:49187 "EHLO smtp6.pp.htv.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754512AbYAISXe (ORCPT ); Wed, 9 Jan 2008 13:23:34 -0500 Date: Wed, 9 Jan 2008 20:22:50 +0200 From: Adrian Bunk To: Zachary Amsden Cc: Rene Herman , Christer Weinigel , "David P. Reed" , Avi Kivity , Ondrej Zary , "H. Peter Anvin" , Bodo Eggert <7eggert@gmx.de>, Ingo Molnar , Alan Cox , Paul Rolland , Pavel Machek , Thomas Gleixner , linux-kernel@vger.kernel.org, Ingo Molnar , rol Subject: Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. Message-ID: <20080109182250.GB4394@does.not.exist> References: <200801081810.58904.linux@rainbow-software.org> <4783B1B2.6070005@reed.com> <200801081838.16241.linux@rainbow-software.org> <4783C4A6.9060402@reed.com> <20080108185120.3ff7ed18@lxorguk.ukuu.org.uk> <4783CBD9.7020709@reed.com> <1199847162.7369.323.camel@bodhitayantram.eng.vmware.com> <20080109063052.48a5709c@weinigel.se> <4784E7E1.4060308@keyaccess.nl> <1199902644.7369.355.camel@bodhitayantram.eng.vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1199902644.7369.355.camel@bodhitayantram.eng.vmware.com> User-Agent: Mutt/1.5.17 (2007-12-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1918 Lines: 47 On Wed, Jan 09, 2008 at 10:17:24AM -0800, Zachary Amsden wrote: > On Wed, 2008-01-09 at 16:27 +0100, Rene Herman wrote: > > On 09-01-08 06:30, Christer Weinigel wrote: > > I'd not expect very time crtical. The current outb_p use gives a delay > > somewhere between .5 and 2 microseconds as per earlier survey meaning a > > udelay(1) or 2 would be enough -- again, at the point that udelay() is sensible. > > > > New machines don't use the legacy PIC anymore anyway. > > > > > The floppy controller code uses outb_p. Even though there might be > > > floppy controllers on modern systems, I'd rather leave the floppy code > > > alone since it's supposed to be very fragile. If you still use > > > floppies you deserve what you get. > > > > Floppies forever. In practice, leaving it alone isn't going to matter, but > > in that same practice changing it to udelay() probably doesn't either. The > > ones to leave alone are the ones that are clumsy/impossible to test and the > > ones such as in NIC drivers that were specifically tuned. > > I'm speaking specifically in terms of 64-bit platforms here. Shouldn't > we unconditionally drop outb_p doing extra port I/O on 64-bit > architectures? Especially considering they don't even have an ISA bus > where the decode timing could even matter? >... I don't think the latter statement was true - AFAIR there are Alphas with ISA slots. > Agree. > > Zach cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/