Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753367AbYCPTlJ (ORCPT ); Sun, 16 Mar 2008 15:41:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752434AbYCPTky (ORCPT ); Sun, 16 Mar 2008 15:40:54 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:41087 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752402AbYCPTkx (ORCPT ); Sun, 16 Mar 2008 15:40:53 -0400 Date: Sun, 16 Mar 2008 12:39:43 -0700 (PDT) From: Linus Torvalds To: Alan Cox cc: Bartlomiej Zolnierkiewicz , Anders Eriksson , "Rafael J. Wysocki" , Jens Axboe , Ingo Molnar , Linux Kernel Mailing List Subject: Re: Linux 2.6.25-rc4 In-Reply-To: <20080316185602.79064f7c@core> Message-ID: References: <20080316140118.891732DC044@tippex.mynet.homeunix.org> <200803161907.04581.bzolnier@gmail.com> <20080316185602.79064f7c@core> User-Agent: Alpine 1.00 (LFD 882 2007-12-20) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 868 Lines: 23 On Sun, 16 Mar 2008, Alan Cox wrote: > > No it doesn't. DRQ simply means "drive has more data for the controller > if you want it". Interrupts are controlled via IEN and the interrupt line. A _lot_ of chips require you to clear the DRQ by taking the data they have. > If the drive wants to give us data and we end the transaction that is > fine. In practice a tiny few devices crap themselves if we don't. More than a few tiny devices from what I remember. It tends to be the other way around - most devices do *not* want to get new commands until you've finished the previous one by draining the queues. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/