[syslinux] Problems booting on Intel i9x5 motherboards.

[H. Peter Anvin]

Pat Suwalski wrote:
> 
> This also occurred to me and seems most likely. To test the booting 
> method a little more, I'm experimenting with using the execute() 
> function of menu.c and replaced it with the function from libmenu (sets 
> EAX to 0003 instead of 0016, not sure what that is). Anyway, I still get 
> the same results, which further pushes the theory that something is left 
> over in memory.
> 

It can't just be "left over" in memory, but something has to have been 
actually *corrupt* in a way that the kernel can't avoid stumbling over it.

That all points towards a BIOS issue.  Those are painfully hard to 
debug, usually, and simulators don't help... I have at least once had 
one that stumped me until I had an opportunity to use an ICE on the system.

> This is where it gets really interesting. I start menu.c32, exit 
> menu.c32, start simple.c32, it works. However, I try my boot option in 
> simple.c32 and it fails just as menu.c32 directly. menu.c32 is 
> definitely leaving something around.

What if you boot it directly from simple.c32?  Does it work then?

>> * Alternately you can start inserting print statements in the menu.c32 
>> code to try to find what is going on.
>> BTW, can VMWare/Bochs/... emulate i9x5 motherboards? Then we can try 
>> to see if it i9x5 is the problem or just that you got a bad batch of 
>> machines.
> 
> Yeah, I use QEmu a lot. It doesn't get affected by this, and it even 
> works on the machines that have problems natively. VMWare seems to often 
> exhibit the problems that the host machine has, though. Regardless, I 
> have about a dozen i9x5's that work just fine with all this.

So it's not even just i9x5... it's something specific to one machine. 
Any thing characteristic, e.g. BIOS, expansion cards?

	-hpa