From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by oss.sgi.com id ; Mon, 5 Feb 2001 13:15:26 -0800 Received: from stereotomy.lineo.com ([64.50.107.151]:57359 "HELO stereotomy.lineo.com") by oss.sgi.com with SMTP id ; Mon, 5 Feb 2001 13:15:00 -0800 Received: from Lineo.COM (localhost.localdomain [127.0.0.1]) by stereotomy.lineo.com (Postfix) with ESMTP id 2C41B4CE9E; Mon, 5 Feb 2001 14:14:48 -0700 (MST) Message-ID: <3A7F17C7.4070406@Lineo.COM> Date: Mon, 05 Feb 2001 14:14:47 -0700 From: Quinn Jensen Organization: Lineo, Inc. User-Agent: Mozilla/5.0 (X11; U; Linux 2.2.16-9mdk i686; en-US; m18) Gecko/20001107 Netscape6/6.0 X-Accept-Language: en MIME-Version: 1.0 To: jsun@hermes.mvista.com Cc: Ralf Baechle , linux-mips@oss.sgi.com Subject: Re: NFS root with cache on References: <3A79C869.2040001@Lineo.COM> <20010204194451.A26868@bacchus.dhis.org> <3A7ED9EB.6080801@Lineo.COM> <3A7EEBD6.F4743A97@mvista.com> <3A7EF431.2060903@Lineo.COM> <3A7EFBC7.9B7D6AF9@mvista.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;linux-mips-outgoing jsun@hermes.mvista.com wrote: >> >> I have tried that in this case but it didn't help, >> because the receive skb data pointers all point to >> the KSEG0 view of the data anyway. > > > I looked into similar problems a while back. If I remeber correctly, the data > pointers do point to kseg0. It is up to the driver to do appropriate > dma_cache_invalidate() (or some functions to that effect) at certain places. Yes, the tulip driver calls pci_unmap_single() on the receive buffer, but for mips (in asm-mips/pci.h) this call does nothing. And this is what is so confusing. Only if the receive buffer was forced to be in KSEG1 would this make sense. > > What is the CPU? It seems logical to suspect about the dma cache routines. Yes, I have scrubbed over my patch to the cache routines many times, especially since on the IDT 334 the cache-way selection for indexed cache ops is weird--they left the way-bit up at bit 12 as if it were an 8KB cache, when in reality it is only a 2KB cache. Quinn