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Does grub crash UNDI service?

From: Feng Shuo
Subject: Does grub crash UNDI service?
Date: Fri, 19 Mar 2004 15:28:11 +0800

I’m working on the UNDI driver of the GRUB diskless patch. The driver
(from etherboot-5.3.5) now works fine before I do any I/O operations.
That is, the diskless GRUB can do DHCP proper, but dies on downloading
kernel. It even dies on loading kernel from local disk (the disk gets
busy and GRUB doesn't respond any more). Two points are suspicious:
1.      UNDI is resident in the high end of the lower memory and
modifies the BIOS FBMS (at 40:13h) to avoid being crashed by the OS
(i.e. GRUB) to load. After loaded, the Etherboot UNDI driver will
release some unused UNDI data, allocate new space to install UNDI API
and modify the FBMS to the new value. ---- I don't know where the GRUB
always examines FBMS before it tries to write on the high end of the
lower memory. If not, GRUB may have crashed the UNDI data before it call
the driver again :(
2.      UNDI uses interrupt, so the UNDI driver set a
'trivial_irq_handler' after it is initialized. That seems to work fine
at start, but I don't know whether it conflicts with grub I/O mechanic
after grub get control. (The driver uses only one irq specified by UNDI
ROM, but do not uninstall it until it is disabled)

If the problem is fixed, we could support any NICs with PXE with it :).
Many thanks.

Feng Shuo
Email: address@hidden
National Engineering Centre for High Performance Computer
Institute of Computing Technology,Chinese Academy of Sciences
6,Kexueyuan Road South,
Haidian District, Beijing,China

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