Date: Tue, 16 Jan 2001 12:49:17 -0500 From: Mike Tancsa <mike@sentex.net> To: Richard Hodges <rh@matriplex.com> Cc: freebsd-atm@FreeBSD.ORG Subject: Re: ATM under 4.x STABLE (DMA and en driver ?) Message-ID: <5.0.1.4.0.20010116121839.033a2a70@marble.sentex.ca> In-Reply-To: <Pine.BSF.4.10.10101160907280.676-100000@mail.matriplex.com > References: <5.0.1.4.0.20010116114713.033bd7c0@marble.sentex.ca>
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At 09:18 AM 1/16/01 -0800, Richard Hodges wrote:
>On Tue, 16 Jan 2001, Mike Tancsa wrote:
> >
> > en0: <Efficient Networks ENI-155p> mem 0xfe000000-0xfe3fffff irq 11 at
> > device 8.0 on pci1
> > en0: unexpected timeout in rx DMA test
> > en0: WARNING: DMA test detects a broken PCI chipset!
> > trying to work around the problem... but if this doesn't
> > work for you, you'd better switch to a newer motherboard.
>
>Ouch! Looking at /usr/src/sys/dev/en/midway.c I see some very interesting
>notes about broken DMA in the Efficient card (but not Adaptec). The
>driver is supposed to work around that, though. Your DMA message above
>seems to refer to the chipset not being able to handle "misaligned 64
>byte DMA", which might not be a major problem, but just might reduce
>the performance.
>
>Of course, the real authority is Chuck Cranor himself...
Hmmm... Any guesses as to how much of a performance drop ? If its a
hardware issue, I wonder if the LINUX crowd has run into this. Time to do
some more archive searching!
BTW, for my simple protocol requirements, should I try and pick up a couple
of used Fore cards instead ? I am hoping the box will be able to forward
30-50Mb/s over its life time.
---Mike
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