From owner-freebsd-hackers Wed Jun 7 17: 1:57 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from overcee.netplex.com.au (peter1.corp.yahoo.com [208.48.107.4]) by hub.freebsd.org (Postfix) with ESMTP id 1973B37B8EC; Wed, 7 Jun 2000 17:01:54 -0700 (PDT) (envelope-from peter@netplex.com.au) Received: from netplex.com.au (localhost [127.0.0.1]) by overcee.netplex.com.au (Postfix) with ESMTP id 6AC291CE1; Wed, 7 Jun 2000 17:01:53 -0700 (PDT) (envelope-from peter@netplex.com.au) X-Mailer: exmh version 2.1.1 10/15/1999 To: Mike Smith Cc: Dennis , hackers@FreeBSD.ORG Subject: Re: if_dc in v4.0 - Forcing store and forward? In-Reply-To: Message from Mike Smith of "Wed, 07 Jun 2000 16:40:33 PDT." <200006072340.QAA01962@mass.cdrom.com> Date: Wed, 07 Jun 2000 17:01:53 -0700 From: Peter Wemm Message-Id: <20000608000153.6AC291CE1@overcee.netplex.com.au> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Mike Smith wrote: > > > > Running a Dlink quad card (570TX) in 100Mb/s full dup mode the driver > > complains about underruns for awhile and then ultimately sets > > store_and_forward which seems to make it work. > > > > Is there a way to force this easily? It seems that it should certainly be > > the default if full dup 100 mode is detected as the other settings fail > > quite easily on rather trivial activities. > > > > should this card be used with the if_dc or if_de driver? Both seem to probe > > it successfully, although both drivers have the same (annoying) underrun > > problem (that wasnt a problem or at least not screen-verbalized in 3.4). > > Transmit underrun is usually caused by another peripheral hogging the PCI > bus; either a poorly configured card with an excessive latency value, or > a misconfigured card (due to BIOS bugs), or a card that otherwise ignores > the PCI latency rules, or a system with too many busy busmaster cards. I am yet to see a 2114x based system that does not do this. My sample set is 21140A (SMC 9332BDT), some 21142's and 21143's. Most Digital labeled but even the Intel ones do it. This happens in BX chipset, VIA MVP chipsets, the PC164SX motherboard under SRM, etc. I have even seen frequent underruns with *no other bus activity* except the CPU fetching code for ttcp and the busmaster DMA to/from the ttcp processes. ie: no DISK, no VGA cards, nothing else at all active. I have checked all the latency timers on all devices as well, they are all set sensibly. I suspect a generic chipset fault, or some design quirk that we are not working around. Note that the windoze drivers for these devices put them permanently in store-and-forward mode. if_de has the exact same problem on all of the systems above. Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message