Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267737AbUIXDMT (ORCPT ); Thu, 23 Sep 2004 23:12:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267702AbUIXDML (ORCPT ); Thu, 23 Sep 2004 23:12:11 -0400 Received: from shawidc-mo1.cg.shawcable.net ([24.71.223.10]:22858 "EHLO pd3mo2so.prod.shaw.ca") by vger.kernel.org with ESMTP id S267325AbUIXDIa (ORCPT ); Thu, 23 Sep 2004 23:08:30 -0400 Date: Thu, 23 Sep 2004 21:07:59 -0600 From: Robert Hancock Subject: Re: PCI Burst To: linux-kernel Message-id: <003901c4a1e3$b2ae1de0$6601a8c0@northbrook> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Mailer: Microsoft Outlook Express 6.00.2900.2180 Content-type: text/plain; reply-type=original; charset=iso-8859-1; format=flowed Content-transfer-encoding: 7bit X-Priority: 3 X-MSMail-priority: Normal References: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1772 Lines: 46 Two things that I'd check, that the memory range shows up as prefetchable (i.e. in lspci) and also that the memory region is mapped with ioremap and not ioremap_nocache. Also, what's the region defined as in /proc/mtrr? I think it has to be mapped as write-back for burst reads to work. When the CPU reads in a cache line in that memory range from the bus, that should hopefully get passed through as a burst read on the PCI bus, but that may be chipset-dependent. Getting PIO-mode PCI reads and writes like this to work efficiently seems a rather difficult thing to do.. ----- Original Message ----- From: "Brian McGrew" Newsgroups: fa.linux.kernel To: Sent: Thursday, September 23, 2004 7:22 PM Subject: PCI Burst > Running RedHat 7.3 with the 2.4.20 kernel. > > How do I enable PCI burst mode for reading and writing on the PCI bus? We > mmap 128MB per board that we install and now that we've added our > addressing to the /proc/mtrr file, we can burst on write but we're not > seeing any burst on the read. > > Any ideas? > > -brian > > Brian D. McGrew {brian@doubledimension.com || pacemakertaker@rock.com } > --- >> Failure is not an option; it is included with every Microsoft product. > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/