From owner-freebsd-hackers Thu Jul 13 14:36:43 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id OAA28450 for hackers-outgoing; Thu, 13 Jul 1995 14:36:43 -0700 Received: from gndrsh.aac.dev.com (gndrsh.aac.dev.com [198.145.92.241]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id OAA28444 for ; Thu, 13 Jul 1995 14:36:40 -0700 Received: (from rgrimes@localhost) by gndrsh.aac.dev.com (8.6.11/8.6.9) id OAA29152; Thu, 13 Jul 1995 14:36:29 -0700 From: "Rodney W. Grimes" Message-Id: <199507132136.OAA29152@gndrsh.aac.dev.com> Subject: Re: NCR PCI needs BOUNCE_BUFFERS? To: terry@uivlsi.csl.uiuc.edu (Terry Lee) Date: Thu, 13 Jul 1995 14:36:29 -0700 (PDT) Cc: freebsd-hackers@freebsd.org In-Reply-To: <199507131820.AA01603@uivlsi.csl.uiuc.edu> from "Terry Lee" at Jul 13, 95 01:20:40 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 1974 Sender: hackers-owner@freebsd.org Precedence: bulk > > I helped a friend install FreeBSD-2.0.5-950622-SNAP on his new Pentium > PC last night. Everything went fine, so I went ahead and configured a new > custom kernel for him. Since the only bus master card is an NCR 825 SCSI host > adapter, I disabled BOUNCE_BUFFERS. But then the disk would only work for > a few seconds before getting "COMMAND FAILED" errors. Enabling BOUNCE_BUFFERS > fixed the problem. Is BOUNCE_BUFFERS needed for PCI systems with no ISA > bus master cards? BOUCE_BUFFERS should not be required on machines that have no ISA bus masters. And specifically PCI machines running the NCR 53C8xx controllers should not require them. Every thing I am currently building and shipping runs just fine without bounce buffers, and these are all PCI NCR 53C810 based systems useing either ASUS Triton motherboards (2 models) or ASUS Saturn II 486 boards. I have seen occasional NCR command failed's during boots, but I am running 2.1-STABLE and there are a few patches in 2.2-CURRENT that need some more ringing out before being pulled to the branch, though they do look to not cause any problems at all and solve several. I would suggest trying a 2.2-CURRENT kernel, but a massive vm change just went in so I am not sure if you want to do that. You might just grab the ncr.c driver, as I recall the changes to it being all stand alone with no other files effected and see if that fixes the problem for you. I think the reason that it goes away when you enable bounce buffers is either a speed issue, or possibly, but not very lickely, cache bug in the MB you are using. > By the way, my friend (a Linux user) decided to give FreeBSD a try > because apparently the Linux NCR driver does not support wide disks yet. He > was pretty impressed by the installation program. Good job guys! :_) -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Reliable computers for FreeBSD