From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933835AbcCOD2O (ORCPT ); Mon, 14 Mar 2016 23:28:14 -0400 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:42005 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932131AbcCOD2L (ORCPT ); Mon, 14 Mar 2016 23:28:11 -0400 Date: Tue, 15 Mar 2016 14:27:29 +1100 (AEDT) From: Finn Thain To: Hannes Reinecke cc: "James E.J. Bottomley" , "Martin K. Petersen" , Michael Schmitz , linux-m68k@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Ondrej Zary , Sam Creasey Subject: Re: [PATCH 20/22] atari_scsi: Set a reasonable default for cmd_per_lun In-Reply-To: <56E66CF5.2070200@suse.de> Message-ID: References: <20160314042700.596192247@telegraphics.com.au> <20160314042705.846189331@telegraphics.com.au> <56E66CF5.2070200@suse.de> 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 On Mon, 14 Mar 2016, Hannes Reinecke wrote: > On 03/14/2016 05:27 AM, Finn Thain wrote: > > This setting does not need to be conditional on Atari ST or TT. > > > > Without TCQ support, cmd_per_lun == 2 is probably reasonable... > > > > Signed-off-by: Finn Thain > > > > --- > > drivers/scsi/atari_scsi.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > Index: linux/drivers/scsi/atari_scsi.c > > =================================================================== > > --- linux.orig/drivers/scsi/atari_scsi.c 2016-03-14 15:26:45.000000000 +1100 > > +++ linux/drivers/scsi/atari_scsi.c 2016-03-14 15:26:55.000000000 +1100 > > @@ -750,6 +750,7 @@ static struct scsi_host_template atari_s > > .eh_abort_handler = atari_scsi_abort, > > .eh_bus_reset_handler = atari_scsi_bus_reset, > > .this_id = 7, > > + .cmd_per_lun = 2, > > .use_clustering = DISABLE_CLUSTERING, > > .cmd_size = NCR5380_CMD_SIZE, > > }; > _2_ ? Are you being overly cheeky here? > I sincerely doubt the driver is capable of submitting two > simultaneous commands ... Right. The LLD has LU busy flags to prevent a LU from being issued more than one command. > Care to explain? It seemed harmless and it is consistent with the all of the other 5380 drivers. I don't know why it was done that way. Perhaps it was done to create a pipeline. That is, to keep a small number of commands in the LLD issue queue so that the NCR5380_main() work item does not have to terminate and then get requeued needlessly. -- > > Cheers, > > Hannes >