General LinuxBIOS Questions
Eric W Biederman
ebiederman at lnxi.com
Mon Sep 16 22:50:00 CEST 2002
Ronald G Minnich <rminnich at lanl.gov> writes:
> oops, missed this message and sent a reply to a reply!
> On 16 Sep 2002, Eric W Biederman wrote:
> > NIC hardware is noticeably more complex than serial ports so getting
> > a network console going from power on is still an open issue. I don't
> > know that it has been tested much yet.
> we're going to try this using myrinet hardware. I.e. a very simple control
> program on the NIC that will give us "serial port" in linuxbios for the
> very early startup.
Sounds good. And I guess with hardware like myrinet with it's own
processor and ram you can do a lot of interesting things.
Right now the serial port hardware has the advantage on
PC's in that it is on the same bus as the rom chip. The one part
of the machine that is alive and working at power on.
I could not debug my P64H2 pci lockup fix with anything on the pci
bus. And I cannot use any NIC that uses DMA until the Ram is
initialized. The bottleneck is both DMA'ing from ROM which might
be possible, and getting the MAC address (or equivalent) into some
place you can DMA from.
If I had to work with a simple chipset with very little redundancy
then I guess a serial port would not have a real advantage. But while
my best option are Intels 12 dozen hub monsters I like having a
console on the most reliable path.
This is a BIOS developer perspective. But it is so cool to have some
one else tell you where your BIOS locks up do to hardware bugs. Today
there is a mature serial port infrastructure that works well, and I
really like it.
I suspect I will like network consoles if I ever get beyond debugging
BIOS issues. And I certainly support network consoles.
Has anyone else on the list had to fix problems where components with
the same part number do not behave identically, but the both
components were behaving correctly?
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