Messages in this thread | | | Date | Thu, 14 Mar 2002 13:26:50 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: IO delay, port 0x80, and BIOS POST codes |
| |
On Thu, 14 Mar 2002, Richard B. Johnson wrote: > > Well I can see why he's an EX-Phoenix BIOS developer. A port at 0xed > does not exist on any standard or known non-standard Intel/PC/AT > compatible.
Note that "doesn't exist" is actually a _bonus_. It means that no controller will answer to it, which causes the IO to time out, which on a regular ISA bus will also take the same 1us. Which is what we want.
Real ports with real controllers can be faster - they could, for example, be fast motherboard PCI ports and be positively decoded and be faster than 1us.
Linus
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |