From owner-freebsd-scsi Mon Apr 20 15:41:14 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id PAA13989 for freebsd-scsi-outgoing; Mon, 20 Apr 1998 15:41:14 -0700 (PDT) (envelope-from owner-freebsd-scsi@FreeBSD.ORG) Received: from ns2.cetlink.net (root@ns2.cetlink.net [209.54.54.20]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id WAA13900 for ; Mon, 20 Apr 1998 22:40:32 GMT (envelope-from jak@cetlink.net) Received: from EXIT10 (i485-gw.cetlink.net [209.198.15.97]) by ns2.cetlink.net (8.8.5/8.8.5) with SMTP id SAA14504; Mon, 20 Apr 1998 18:40:09 -0400 (EDT) From: jak@cetlink.net (John Kelly) To: "Justin T. Gibbs" Cc: scsi@FreeBSD.ORG Subject: Re: ahh, I think I see part of the problem.. (CAM bouncing) Date: Mon, 20 Apr 1998 22:42:17 GMT Message-ID: <353cce7e.94813933@mail.cetlink.net> References: <199804201657.KAA28393@pluto.plutotech.com> In-Reply-To: <199804201657.KAA28393@pluto.plutotech.com> X-Mailer: Forte Agent 1.5/32.451 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by hub.freebsd.org id WAA13925 Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Mon, 20 Apr 1998 10:53:12 -0600, "Justin T. Gibbs" wrote: >>It seems that bus_dmamem_alloc() is flawed if a filter function is active, >>for starters. With a Bt-445S, it's got to bounce the 'paddr % 16MB == >>biosaddr' pages, so the contigmalloc() will allocate pages from the entire >>memory pool (since the 445S has a 32bit dma limit), and yet bouncing may >>still need to happen. Incidently, what happens if contigmalloc() >>allocates a page from the shadow of the bios rom addr? :-) > >Take a good look at the initialization code in bt_isa.c. If we have to >install a filter, we set the address range for the filter to be 16MB->4GB. >bus_dmamem_alloc and the code that allocates bounce pages only allocates >space below the low address specified in the dma tag. This should ensure >that we allocate pages that can replace any page rejected by the filter. >So, the setup for a broken 445S is the same as an ISA card except that we >include a filter that will allow 99% of the pages above 16MB. After reading this I don't understand what's broken about the 445S. Could you put it in more simple language? I have some 445C adapters and I wonder if they have the same characteristic. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message