Re: Clean BIOS booting Mandrake 9 via LILO

Hi,

> My plan is to give both an NFS mount on to a directory on my main
> machine, ssh into both from my main machine, and write a small app
> using mmap() (compiled by one box into the NFS shared directory on
> the main machine, so its visible to both Xboxes) which will allow
> me to fairly easily try all kinds of register copying between the
> machines, all in Linux.  Essentially I hope to copy the register
> guts out of a live, working machine and deliver them into the cold,
> unliving flesh of the video chip on the second, cromwell-booted
> machine to see if We Can Create The Mystical Spark Of Video Life In
> It, using these creepy techniques.

Sounds as if it could be working.

> I had a look through the kernel code you kindly pointed at Oliver,
> and there's clearly a lot of useful stuff in there, especially the
> bunch of helper functions which specify which register pairs hide
> their own personal address/data maps.
>
> There's one thing that's really worrying me, in
> ./drivers/video/riva/nv4ref.h at the beginning are defined "Magic
> values to lock/unlock extended regs"
>
> Do you know what this is about?  

No, not really. The X driver calls LockUnlock(0) (i.e. unlock) every 
time before doing something interesting and LockUnlock(1) (i.e. lock) 
when finished. The kernel fb driver only calls LockUnlock(0), i.e. 
the registers are never locked.

Locking and unlocking looks fairly simple:

static void nv10LockUnlock
(
    RIVA_HW_INST *chip,
    int           LockUnlock
)
{
    VGA_WR08(chip->PCIO, 0x3D4, 0x1F);
    VGA_WR08(chip->PCIO, 0x3D5, LockUnlock ? 0x99 : 0x57);
}

In the fb driver there's some additional code (fbdev.c, ll. 1986):
/* unlock io */
CRTCout(rinfo, 0x11, 0xFF);   /* vgaHWunlock() + riva unlock (0x7F) */

This seems to be native VGA unlock (in X this is handled by the vgahw 
library, common to all VGA chipsets). You'll probably need this as 
well.

Regards,

Oliver




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