Re: problem with GRUB and my BIOS?

[Yoshinori K. Okuji]

On Tuesday 24 January 2006 00:03, Tony and Robyn Lewis wrote:
> Yoshinori K. Okuji wrote:
> >On Saturday 21 January 2006 18:21, Marco Gerards wrote:
> >>In that case it is not exported by the BIOS.  There is nothing GRUB
> >>can do about it...
> >
> >I don't agree. Clearly, his BIOS could boot up the CD itself, and GRUB
> > failed in recognizing the drive.
>
> That sounds about right.  It can boot from the CD (and other install
> CDs) but GRUB doesn't seem to want to find it.
>
> >I always doubt that the drive detection code for CD
> >drives in GRUB is buggy. Unfortunately, I don't have such a drive or BIOS
> >which does not work with GRUB, so I cannot debug it myself.
>
> Is there any debugging I can start to do?

In stage2/bios.c, there is a function get_cdinfo. In your case, the control 
should reach the block which contains the comment:

/* No emulation bootable CD-ROM */

So it is necessary to check what biosdisk_int13_extensions returns (the 
contents of ERR and CDRP). You can print values by grub_printf to your 
screen.

Okuji