From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 14 May 2002 07:09:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 14 May 2002 07:09:46 -0400 Received: from gateway.ukaea.org.uk ([194.128.63.73]:47144 "EHLO fuspcnjc.culham.ukaea.org.uk") by vger.kernel.org with ESMTP id ; Tue, 14 May 2002 07:09:45 -0400 Message-ID: <3CE0F08A.5C41CAFA@ukaea.org.uk> Date: Tue, 14 May 2002 12:10:02 +0100 From: Neil Conway X-Mailer: Mozilla 4.78 [en] (X11; U; Linux 2.4.9-31 i686) X-Accept-Language: en MIME-Version: 1.0 To: Martin Dalecki CC: linux-kernel@vger.kernel.org Subject: Re: [PATCH] 2.5.15 IDE 61 In-Reply-To: <3CE0DDBE.F9EC80AC@ukaea.org.uk> <3CE0D067.6010302@evision-ventures.com> <3CE0E306.6171045B@ukaea.org.uk> <3CE0D952.7080403@evision-ventures.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Martin Dalecki wrote: > There is no problem to go in paralell on different channels for > requests. The serialization has only to be done > for the drive setup. I agree for general chipsets, but my whole point was with regard to buggy chipsets which need to be serialized on both channels. If you're saying that even these broken chipsets are OK with having transfers on one channel while setting up transfers on another channel, then perhaps you are right but that's not what I believed to be the case (can't find info to tell me either way right now). But if that really were the case, then how could the (e.g.) cmd640 problem ever have been manifested? A spinlock is ALWAYS held while ide_do_request is executing. Even if it weren't, only an SMP machine could be trying to program both channels simultaneously because interrupts are disabled too. Neil