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SubjectRe: Can we kill f inb_p, outb_p and other random I/O on port 0x80, in 2.6?
Alan Cox wrote:
> (one part of the problem of course is you need inb_p/outb_p to drive
> the timer chip on some x86 boards in order to calibrate the udelay
> timer)

What sort of timer chip problems do you see? Is it something that can
be auto-detected, so that timer chip accesses can be made faster on
boards where that is fine?

I'm sure I've seen timer chip code in DOS programs that didn't have
the extra delay I/Os. Surely it cannot be a very widespread problem.

> > When debugging this I modified arch/i386/io.h to read:
> > #define __SLOW_DOWN_IO__ ""
> > Which totally removed the delay and the system ran fine.
>
> Not all systems do - we had breakages from both the keyboard controller
> and the timer chips even on some modern boards when this got messed up.

I've also seen much DOS code that didn't have extra delays for
keyboard I/Os. What sort of breakage did you observe with the
keyboard?

Thanks,
-- Jamie
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