From owner-freebsd-hackers  Mon May 13 18:31:56 2002
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Date: Mon, 13 May 2002 18:31:50 -0700
From: Alfred Perlstein <bright@mu.org>
To: David Greenman-Lawrence <dg@root.com>
Cc: Terry Lambert <tlambert2@mindspring.com>,
	Matthew Dillon <dillon@apollo.backplane.com>,
	jamie@tridentmicrosystems.co.uk, freebsd-hackers@FreeBSD.ORG
Subject: Re: Broadcom BCM5701 Chipset problems
Message-ID: <20020514013150.GA1585@elvis.mu.org>
References: <20020513102526.H72322@nexus.root.com> <200205131758.g4DHwJFj068941@apollo.backplane.com> <3CE00B14.E8CA43A8@mindspring.com> <200205131901.g4DJ1U8s069604@apollo.backplane.com> <3CE01595.D045B70D@mindspring.com> <20020513124807.R72322@nexus.root.com> <3CE01A3A.AAB85F64@mindspring.com> <20020513130924.W72322@nexus.root.com> <20020513205636.GB90188@elvis.mu.org> <20020513153828.A83723@nexus.root.com>
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* David Greenman-Lawrence <dg@root.com> [020513 15:40] wrote:
> >* David Greenman-Lawrence <dg@root.com> [020513 13:10] wrote:
> >> 
> >>    The card doesn't drop the packet if the IP/TCP checksum is wrong. In my
> >> tests, I did a software checksum on the supposedly bad packet, and found it
> >> to be good every time. So it DMA's correctly, the checksum is just calculated
> >> incorrectly by the hardware.
> >
> >Probably pretty obvious, but adding a flag "if bad hwsum, then try softsum"
> >probably wouldn't be too hard.
> 
>    Not obvious at all. How do you know if a packet is good or bad without
> always doing the software checksum?

I guess I incorrectly assumed that the card only had a problem with
falsely marking packets as bad, and not marking bad ones as good.

Sorry.

-Alfred

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