From owner-freebsd-hackers Thu Oct 28 8:29: 0 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from etinc.com (et-gw.etinc.com [207.252.1.2]) by hub.freebsd.org (Postfix) with ESMTP id AC69214DAB for ; Thu, 28 Oct 1999 08:28:51 -0700 (PDT) (envelope-from dennis@etinc.com) Received: from dbsys (dbsys.etinc.com [207.252.1.18]) by etinc.com (8.9.3/8.9.3) with SMTP id LAA04413; Thu, 28 Oct 1999 11:25:47 -0400 (EDT) Message-Id: <199910281525.LAA04413@etinc.com> X-Sender: dennis@etinc.com X-Mailer: QUALCOMM Windows Eudora Pro Version 4.0 Date: Thu, 28 Oct 1999 10:27:53 -0400 To: eT@post.com, hackers@FreeBSD.ORG From: Dennis Subject: Re: PCI bus Latency In-Reply-To: <19991027083557.22017.rocketmail@web1402.mail.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG At 01:35 AM 10/27/99 -0700, eT wrote: >Greetings .. > >When doing a pci_read_config(dev, PCI_LATENCY_TIMER, 4) I get varying values on >different hardware configurations. > >On Machine A the value is 32 and my device driver (using DMA) works fine. > >On Machine B the value is 64 and my device driver doesn't work fine - there >seem >s to be these hickups in which the Chip writing to the PCI controller says it >ha >s finished transferring data but the write counters are still > 0. My card >works closely with two network cards in the system. > >Actually, I reckon I just need some pointers and things to remember when it >come >s to dealing with latency. Any help? It seems unlikely that the latency timer will cause a controller to "not work" The latency timer settings allow a master to tell the system how long it needs to complete a burst cycle...however a controller is allowed to complete the current cycle when another master grants the bus so you shouldnt have failures unless the controller is defective. Dennis To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message