Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops

H. Peter Anvin
2007-12-11T00:32:15Z

Rene Herman wrote:
>
> By the way, David, it would be interesting if you could test 0xed. If
> your problem is some piece of hardware getting upset at LPC bus aborts
> it's not going to matter and we'd know an outb delay is just not an
> option on your system at least. You said you could quickly reproduce the
> problem with port 0x80?
>

I tried 0xED for a few versions (1.31-1.37) of SYSLINUX. It broke on a
lot of hardware (Phoenix BIOS uses 0xED by default, but BIOSes don't
have to work on arbitrary hardware.)

-hpa