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 07:24:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 14 May 2002 07:24:50 -0400 Received: from [195.63.194.11] ([195.63.194.11]:25867 "EHLO mail.stock-world.de") by vger.kernel.org with ESMTP id ; Tue, 14 May 2002 07:24:49 -0400 Message-ID: <3CE0E538.5040502@evision-ventures.com> Date: Tue, 14 May 2002 12:21:44 +0200 From: Martin Dalecki User-Agent: Mozilla/5.0 (X11; U; Linux i686; pl-PL; rv:1.0rc1) Gecko/20020419 X-Accept-Language: en-us, pl MIME-Version: 1.0 To: Neil Conway 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> <3CE0F08A.5C41CAFA@ukaea.org.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Uz.ytkownik Neil Conway napisa?: > 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. Well in the next patch round the hwgroup will be replaced with a spin lock, which is supposed to be shared between channels which need forced access serialization between them. Please look at patches 62a and 63 :-).