From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 26 Jan 2001 10:31:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 26 Jan 2001 10:31:49 -0500 Received: from pcep-jamie.cern.ch ([137.138.38.126]:59151 "EHLO pcep-jamie.cern.ch") by vger.kernel.org with ESMTP id ; Fri, 26 Jan 2001 10:31:42 -0500 Date: Fri, 26 Jan 2001 16:31:03 +0100 From: Jamie Lokier To: Mark Hahn Cc: linux-kernel@vger.kernel.org Subject: Re: Linux Post codes during runtime, possibly OT Message-ID: <20010126163103.F7096@pcep-jamie.cern.ch> In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from hahn@coffee.psychology.mcmaster.ca on Fri, Jan 26, 2001 at 10:15:02AM -0500 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Mark Hahn wrote: > > #ifdef SLOW_IO_BY_JUMPING > > #define __SLOW_DOWN_IO "\njmp 1f\n1:\tjmp 1f\n1:" > > #else > > -#define __SLOW_DOWN_IO "\noutb %%al,$0x80" > > +#define __SLOW_DOWN_IO "\noutb %%al,$0x19" > > this is nutty: why can't udelay be used here? empirical measurements > in the thread show the delay is O(2us). Does anyone remember where __SLOW_DOWN_IO is needed any more? udelay() makes sense. Modern drivers use small udelays themselves to confirm to chip specs. Some ISA drivers appear to use outb_p "just to be on the safe side", no idea if it's appropriate or not. Some even mix outb and outb_p based on educated guesses. I know, I've written such code :-) -- Jamie - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/