From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 01/22] g_ncr5380: Remove CONFIG_SCSI_GENERIC_NCR53C400 Date: Mon, 14 Mar 2016 08:21:07 +0100 Message-ID: <56E66663.2030704@suse.de> References: <20160314042700.596192247@telegraphics.com.au> <20160314042700.855969695@telegraphics.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mx2.suse.de ([195.135.220.15]:54919 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754841AbcCNHVM (ORCPT ); Mon, 14 Mar 2016 03:21:12 -0400 In-Reply-To: <20160314042700.855969695@telegraphics.com.au> Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Finn Thain , "James E.J. Bottomley" , "Martin K. Petersen" , Michael Schmitz , linux-m68k@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ondrej Zary , Sam Creasey On 03/14/2016 05:27 AM, Finn Thain wrote: > This change brings a number of improvements: fewer macros, better tes= t > coverage, simpler code and sane Kconfig options. The downside is a sm= all > chance of incompatibility (which seems unavoidable). >=20 > CONFIG_SCSI_GENERIC_NCR53C400 exists to enable or inhibit pseudo DMA > transfers when the driver is used with 53C400-compatible cards. Thank= s to > Ondrej Zary's patches, PDMA now works which means it can be enabled > unconditionally. >=20 > Due to bad design, CONFIG_SCSI_GENERIC_NCR53C400 ties together unrela= ted > functionality as it sets both PSEUDO_DMA and BIOSPARAM macros. This p= atch > effectively enables PSEUDO_DMA and disables BIOSPARAM. >=20 > The defconfigs and the Kconfig default leave CONFIG_SCSI_GENERIC_NCR5= 3C400 > undefined. Red Hat 9 and CentOS 2.1 were the same. This leaves both > PSEUDO_DMA and BIOSPARAM disabled. The effect of this patch should be > better performance from enabling PSEUDO_DMA. >=20 > On the other hand, Debian 4 and SLES 10 had CONFIG_SCSI_GENERIC_NCR53= C400 > enabled, so both PSEUDO_DMA and BIOSPARAM were enabled. This patch mi= ght > affect configurations like this by disabling BIOSPARAM. My best guess= is > that this could be a problem only in the vanishingly rare case that > 1) the CHS values stored in the boot device partition table are wrong= and > 2) a 5380 card is in use (because PDMA on 53C400 used to be broken). >=20 > Signed-off-by: Finn Thain >=20 > --- >=20 Reviewed-by: Hannes Reinecke And don't worry about SLES10; we won't backport your fixes to _that_. Cheers, Hannes --=20 Dr. Hannes Reinecke Teamlead Storage & Networking hare@suse.de +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: F. Imend=F6rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG N=FCrnberg)