From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757837AbZJaN4b (ORCPT ); Sat, 31 Oct 2009 09:56:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757805AbZJaN4a (ORCPT ); Sat, 31 Oct 2009 09:56:30 -0400 Received: from rtr.ca ([76.10.145.34]:55940 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757794AbZJaN4a (ORCPT ); Sat, 31 Oct 2009 09:56:30 -0400 Message-ID: <4AEC420A.9030502@rtr.ca> Date: Sat, 31 Oct 2009 09:56:26 -0400 From: Mark Lord Organization: Real-Time Remedies Inc. User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Robert Hancock Cc: Philippe De Muyter , linux-ide@vger.kernel.org, davem@davemloft.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH ide] : Increase WAIT_DRQ to support slow CF cards References: <20091026162011.GA3289@frolo.macqel> <4AE64031.5060105@gmail.com> In-Reply-To: <4AE64031.5060105@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Robert Hancock wrote: .. > This has come up before: > > http://marc.info/?l=linux-ide&m=123064513313466&w=2 > > I think this timeout should not even exist. libata has no such timeout > (only the overall command completion timeout), and I can't find any > reference in current ATA specs to the device being required to raise DRQ > in any particular amount of time. .. The reason for the original (20ms, then 50ms) timeout was this text from the ATA1 specification, long since outdated: - Upon receipt of a Class 3 command, the drive sets BSY within 400 nsec, sets up the sector buffer for a write operation, sets DRQ within 20 msec, and clears BSY within 400 nsec of setting DRQ. Cheers