Re: Keyboard lockup with NetBSD5

[Frank Wille <frank%phoenix.owl.de@localhost>]

Ignatios Souvatzis wrote:

>  [..delay..]
>> Ok. I had a look at the 4.0 source. I'm not sure if it had the same
>> precision (it probably has), but it definitely had less overhead.
>
> The resolution is 8 cpu clocks for 68020/68030, 3 cpu clocks for
> 68040 (or was it: 8 for 020, 3 for 030/040 ?) and 1 cpu clock for
> 68060. It's pre-calibrated to the fastest known CPU clocks of each
> type (which might make delays up to three times as long as nominal
> if used on a 16 MHz 68030), and then calibrated when clock.c
> initializes.
> [...]

Then it was clearly better than the current implementation, and I agree that
we should revive the pre-5.0 code here. The new timecounter is completely
independant.


>> A timecounter has to return the current value of a counter with a
>> fixed frequency. How can you do that with a calibrated loop?
>
> Yesyes. But why would that influence the DELAY/delay implementation?

Not at all, from what I have seen. The calibration can still take place
during clock-attachment.


-- 
    _  Frank Wille (frank%phoenix.owl.de@localhost)
 _ //  http://sun.hasenbraten.de/~frank/
 \X/   Phx @ #AmigaGer