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

H. Peter Anvin
2007-12-11T05:59:23Z

Alan Cox wrote:
>> In any case, my machine does not have an ISA bus. Why should it? It's
>> a laptop!
>
> Yes it does. The branding spec said "No ISA bus" so it was renamed "LPC"
> and hidden internally, but its alive and well.
>

Well that, plus it was serialized and uses PCI electricals and timing,
hence the LPC (Low Pin Count) moniker. Its performance is pretty much
exactly ISA, though, and unlike PCI it provides full support for all
legacy ISA features like slave DMA.

-hpa