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

Alan Cox
2007-12-08T21:10:24Z

> The point here is that Linux is NOT using a defined-to-be "unused"
> port. It IS using the "diagnostic" port, and talking to a diagnostic
> device that *is* used, and may be present.

Just like millions of other pieces of software from the same era.

> 2) Start a background task with the maintainers of drivers to clean up
> their code regarding these short delays for slow devices (note that it's
> never because the *bus* is slow, but because the *device* is slow.)
> Perhaps this could be helped by "deprecating" the _p calls and
> suggesting an alternative that requires the coder to be precise about
> what the delay is for, and how long it is supposed to be, perhaps on a
> per-machine basis.

Send patches. For a lot of the devices we know what the requirements are
as its locked to ISA cycle times.

Alan