From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753481AbbLVHpS (ORCPT ); Tue, 22 Dec 2015 02:45:18 -0500 Received: from mx2.suse.de ([195.135.220.15]:43464 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752995AbbLVHpQ (ORCPT ); Tue, 22 Dec 2015 02:45:16 -0500 Subject: Re: [PATCH v3 49/77] ncr5380: Remove redundant ICR_ARBITRATION_LOST test and eliminate FLAG_DTC3181E To: Finn Thain , "James E.J. Bottomley" , Michael Schmitz , linux-m68k@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, "Martin K. Petersen" References: <20151222011737.980475848@telegraphics.com.au> <20151222011751.308030701@telegraphics.com.au> From: Hannes Reinecke Message-ID: <5678FF8A.8030105@suse.de> Date: Tue, 22 Dec 2015 08:45:14 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <20151222011751.308030701@telegraphics.com.au> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/22/2015 02:18 AM, Finn Thain wrote: > Remove FLAG_DTC3181E. It was used to suppress a final Arbitration Lost > (SEL asserted) test that isn't actually needed. The test was suppressed > because it causes problems for DTC436 and DTC536 chips. It takes place > after the host wins arbitration, so SEL has been asserted. These chips > can't seem to tell whether it was the host or another bus device that > did so. > > This questionable final test appears in a flow chart in an early NCR5380 > datasheet. It was removed from later documents like the DP5380 datasheet. > > By the time this final test takes place, the driver has already tested > the Arbitration Lost bit several times. The first test happens 3 us after > BUS FREE (or longer due to register access delays). The protocol requires > that a device stop signalling within 1.8 us after BUS FREE unless it won > arbitration, in which case it must assert SEL, which is detected 1.2 us > later by the first Arbitration Lost test. > > Signed-off-by: Finn Thain > > --- > drivers/scsi/NCR5380.c | 14 +------------- > drivers/scsi/NCR5380.h | 1 - > drivers/scsi/atari_NCR5380.c | 9 --------- > drivers/scsi/dmx3191d.c | 2 +- > drivers/scsi/g_NCR5380.c | 2 +- > 5 files changed, 3 insertions(+), 25 deletions(-) > Reviewed-by: Hannes Reinecke Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)