Re: Does grub crash UNDI service?

[Yoshinori K. Okuji]

On Friday 19 March 2004 08:28, Feng Shuo wrote:
> 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 :(

It's likely. GRUB checks the lower memory only once when it starts up. 
Take a look at stage2/common.c.

> 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)

Is it a real mode interrupt? If so, GRUB does not have any problem, but 
you might have to take care about that GRUB does not stay in protected 
mode too long.

Thanks,
Okuji