Date: Sat, 15 Dec 2001 13:56:35 -0800 From: David Greenman <dg@root.com> To: Terry Lambert <tlambert2@mindspring.com> Cc: Alfred Perlstein <bright@mu.org>, Brooks Davis <brooks@one-eyed-alien.net>, rsharpe@ns.aus.com, freebsd-hackers@FreeBSD.ORG Subject: Re: Does anyone know if the Broadcom BCM5700 has problems with HW csum? Message-ID: <20011215135635.A86349@nexus.root.com> In-Reply-To: <3C1B32EB.ACBA8DB@mindspring.com>; from tlambert2@mindspring.com on Sat, Dec 15, 2001 at 03:24:27AM -0800 References: <3C1AEA9E.6010502@ns.aus.com> <20011214214118.A30560@Odin.AC.HMC.Edu> <3C1AF362.534BD2F7@mindspring.com> <20011215005739.A84861@nexus.root.com> <20011215031304.N79896@elvis.mu.org> <20011215011045.C84861@nexus.root.com> <3C1B32EB.ACBA8DB@mindspring.com>
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>David Greenman wrote: >> Alfred Perlstein wrote: >> >You're probably incorrect, it doesn't matter if vlan tags are active >> >or not, it's most likely wheather or not the firmware is being asked >> >to handle them at all. >> >> I would think it would get the checksum wrong most of the time if that >> were the case. It seems to only have problems with small packets, but the >> behavior is pretty strange, so who knows. Do you have some specific knowledge >> about Broadcom and brokeness related to VLAN tag support when not using >> VLANs? > >If it's very small payload, it's probably a byte-order-in-buffer >issue (several Eagle manufactured cards had similar problems, and >so did the NE1000, when it came to DMA transfers, back when 16 bit >transfers were new 8^). The packet itself is fine, it's just the checksum that the hardware calculates is wrong. >For VLANs, yes, there are specific problems known with the Broadcom >cards when the firmware support for VLANs is enabled. The first card >known to work with checksum offload enable and VLAN support enabled >(whether it's used or not) is the Tigon III. I don't know if Bill >Paul fixed the firmware for the Tigon II in this case (he has been >known to hack Tigon II firmware), but it could have been fixed by now. > >In any case, disabling it is what ClickArray ended up doing, as well, >for the Tigon II, until the firmware could be fixed. We're talking about the Tigon III (bge driver for Broadcom BCM5700/BCM5701). -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org President, TeraSolutions, Inc. - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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