From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262116AbTFXOOq (ORCPT ); Tue, 24 Jun 2003 10:14:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262127AbTFXOOq (ORCPT ); Tue, 24 Jun 2003 10:14:46 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:23216 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262116AbTFXOOp (ORCPT ); Tue, 24 Jun 2003 10:14:45 -0400 Message-ID: <3EF86019.3090608@pobox.com> Date: Tue, 24 Jun 2003 10:28:41 -0400 From: Jeff Garzik Organization: none User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021213 Debian/1.2.1-2.bunk X-Accept-Language: en MIME-Version: 1.0 To: Bartlomiej Zolnierkiewicz CC: Jan-Benedict Glaw , axboe@suse.de, linux-kernel@vger.kernel.org Subject: Re: Testing IDE-TCQ and Taskfile - doesn't work nicely:) References: In-Reply-To: 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 Bartlomiej Zolnierkiewicz wrote: > TCQ shouldn't be enabled on hdc, you have two drives on second ide > channel and current TCQ driver design allows only one drive per channel, > so proper fix is to not enable TCQ :-). IMO the best rule is "enable TCQ if and only if 100% of the channel supports TCQ". So, two drives on the same channel can do TCQ, if and only if they both support TCQ. That's a big benefit of bus release, after all, simultaneously servicing multiple drives. The device-select and service interrupt semantics are annoying but doable. Jeff