Rene Herman wrote:
I mean that before the linux kernel used a port 0x80 write as an I/O
delay it used a short jump (two in a row actually...) as such and this
was at the time that it actually ran on the old legacy stuff that is of
most concern here.
No, if I'm not mistaken, those two jumps are actually what the udelay()
is going to do anyway as part of delay_loop() at that early stage so
that even before loops_per_jiffy calibration, I believe we should still
be okay.
That doesn't make any sense at all. The whole point why the two jumps
were obsoleted with the P5 (or even late P4, if I'm not mistaken) was
because they were utterly insufficient when the CPU ran at something
much higher than the external speed.
Yes, it's a bit of a "well, hrrm" thing, but, well... loops_per_jiffy
can be initialised a bit more conservatively then today as well (and as
discussed earlier, possibly per CPU family) but I believe it's actually
sort of fine not too worry much about it...
Uhm... no. Quite the contrary, I would say.
-hpa
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