Re: Linux Post codes during runtime, possibly OT

[Jamie Lokier]

Mark Hahn wrote:
> >  #ifdef SLOW_IO_BY_JUMPING
> >  #define __SLOW_DOWN_IO "\njmp 1f\n1:\tjmp 1f\n1:"
> >  #else
> > -#define __SLOW_DOWN_IO "\noutb %%al,$0x80"
> > +#define __SLOW_DOWN_IO "\noutb %%al,$0x19"
> 
> this is nutty: why can't udelay be used here?  empirical measurements
> in the thread show the delay is O(2us).

Does anyone remember where __SLOW_DOWN_IO is needed any more?

udelay() makes sense.  Modern drivers use small udelays themselves to
confirm to chip specs.

Some ISA drivers appear to use outb_p "just to be on the safe side", no
idea if it's appropriate or not.  Some even mix outb and outb_p based on
educated guesses.  I know, I've written such code :-)

-- Jamie


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