[D800] Dell D800 (FBSD 5.2-release) Broadcom BCM5705M MTU/Jumbo Problem

[Jamie Bowden]

On Thu, 22 Jan 2004, David Gilbert wrote:

> >>>>> "Mike" == Mike Hunter <mhunter at ack.Berkeley.EDU> writes:
>
> Mike> Hi everybody, I'm going to be trying to get gigabit throughput
> Mike> between my laptop (Dell Latitude D800 running 5.2-release) and a
> Mike> shuttle box running FreeBSD 5.1 (not in front of me at the
> Mike> moment.)  As part of the process, I attempted to increase the
> Mike> frame size on my laptop, only to be greeted with disappointment:
>
> A few things to think about.  I don't know what disk you got, but the
> 60G disk in mine doesn't appear to be all that fast.  You might be
> able to get memory to memory transfers to be GigE speeds, but your
> hard drive(s) are likely a limit from getting too much speed.

The 40GB disk is 7200 RPM, but the others offered on that model are all
5400RPM.  I was going to order mine with the 60G disk until my Dell rep.
told me that little tidbit.

> Mike> The C file talks about being able to do jumbo frames when the
> Mike> mtu is big enough...anybody know what I'm missing?  My card is a
> Mike> "Broadcom BCM5705M" and I'm running FreeBSD 5.2-release.  When I
> Mike> asked google, it mostly pointed me at comments in if_bge.c
> Mike> talking about jumbo frames :|
>
> Unfortunately, the chip in the D800 is a scaled down version.  It
> doesn't support jumbo frames.  I assume that broadcom sells the
> cripled part at a lower price than the full part.  There are notes in
> the driver about what's diabled in this specific version.

I'm curious why the 800 would have the lower end chip, it's a higher end
laptop all around when compared to the 600.

Jamie Bowden

-- 
"It was half way to Rivendell when the drugs began to take hold"
Hunter S Tolkien "Fear and Loathing in Barad Dur"
Iain Bowen <alaric at alaric.org.uk>