On Tue, Nov 05, 2002 at 01:57:16PM -0500, Richard B. Johnson wrote:
> No! You will break many machines. You cannot use out_p() when
> writing the latch it __must__ be out(). the "_p" puts a write
> to another port between the two writes. That will screw up
> the internal state-machine of most PITs including AMD-SC520.
You make an interesting point. Have you checked if an inb_p() on this hardware
could unlock the latch when reading the first byte ? It may also be one cause
of time jumps if the counter is just about to wrap when it's being read, and
gets unlocked by an out to port 0x80 (the "_p").
> count = inb_p(0x40); /* read the latched count */
> count |= inb(0x40) << 8;
Or perhaps it will be time to change port 0x80 to something else, that no
chipset will use. I've seen 0xED in a bios somewhere, but I don't remember
where.
Cheers,
Willy
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This archive was generated by hypermail 2b29 : Thu Nov 07 2002 - 22:00:39 EST