From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 21/22] atari_scsi: Allow can_queue to be increased for Falcon Date: Mon, 14 Mar 2016 08:58:25 +0100 Message-ID: <56E66F21.2050308@suse.de> References: <20160314042700.596192247@telegraphics.com.au> <20160314042706.096009019@telegraphics.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160314042706.096009019@telegraphics.com.au> Sender: linux-scsi-owner@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 List-Id: linux-m68k@vger.kernel.org On 03/14/2016 05:27 AM, Finn Thain wrote: > The benefit of limiting can_queue to 1 is that atari_scsi shares the > ST DMA chip more fairly with other drivers (e.g. falcon-ide). >=20 > Unfortunately, this can limit SCSI bus utilization. On systems withou= t > IDE, atari_scsi should issue SCSI commands whenever it can arbitrate = for > the bus. Make that possible by making can_queue configurable. >=20 > Signed-off-by: Finn Thain >=20 > --- > drivers/scsi/atari_scsi.c | 83 ++++++++++++-----------------------= ----------- > 1 file changed, 22 insertions(+), 61 deletions(-) >=20 Hmm. We actually have a similar reasoning in the aic7xxx driver, where the driver core wants to setup pointers to the _next_ command. So maybe it makes sense to add a pointer to the 'next' command somewhere in the NCR core structure, to be submitted whenever bus arbitration tells you so? But in the end it really looks like a real issue somewhere in the code, be it the driver or the block/scsi layer. Nevertheless, setting it to '1' is certainly the correct way here. Reviewed-by: Hannes Reinecke 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) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html