Date: Thu, 28 Oct 1999 10:27:53 -0400 From: Dennis <dennis@etinc.com> To: eT@post.com, hackers@FreeBSD.ORG Subject: Re: PCI bus Latency Message-ID: <199910281525.LAA04413@etinc.com> In-Reply-To: <19991027083557.22017.rocketmail@web1402.mail.yahoo.com>
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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
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