From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271499AbTGQPYM (ORCPT ); Thu, 17 Jul 2003 11:24:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271503AbTGQPXy (ORCPT ); Thu, 17 Jul 2003 11:23:54 -0400 Received: from mail2.sonytel.be ([195.0.45.172]:32922 "EHLO witte.sonytel.be") by vger.kernel.org with ESMTP id S271499AbTGQPVw (ORCPT ); Thu, 17 Jul 2003 11:21:52 -0400 Date: Thu, 17 Jul 2003 17:36:25 +0200 (MEST) From: Geert Uytterhoeven To: Linus Torvalds cc: Jeff Garzik , Linux Kernel Mailing List , Alan Cox , Bartlomiej Zolnierkiewicz Subject: Re: Fix IDE initialization when we don't probe for interrupts. In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 9 Jul 2003, Linus Torvalds wrote: > On Wed, 9 Jul 2003, Jeff Garzik wrote: > > I'm curious where interrupts are re-enabled, though? > > The low-level drivers seem to do it at every IO. Don't ask me why. But it > gets done automatically by any code that does > > hwif->OUTB(drive->ctl, IDE_CONTROL_REG); > > which is pretty common (just grep for "IDE_CONTROL_REG" and you'll see > what I mean). > > I note that I should have made this "disable irq" be dependent on > IDE_CONTROL_REG being non-zero. Although I don't see when that register > _can_ be zero, it would be a major bummer not to have access to the > control register. > > (Obviously it must be zero for some architecture, though, or those > conditionals woulnd't make sense. Alan? Bartlomiej? What kind of sick > pseudo-IDE controller doesn't have a control register?). IDE can live without the control register (what do you _really_ need it for?). Hence some hardware doesn't provide it, by leaving out the second bank of 8 IDE registers. Another trick is the `IDE doubler' for Amiga (but I guess you can make it work on any IDE interface): with a few diodes you can map the second bank of 8 IDE registers to a second IDE chain, doubling the number of devices you can attach. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds