From: obz@sisd.kodak.com (Orest Zborowski COMP) Subject: Re: X1.1 and ET4000 card Date: Tue, 7 Jul 1992 14:40:32 GMT
hedrick@dartagnan.rutgers.edu (Charles Hedrick) writes:
>toivo@ucs.uwa.OZ.AU (Toivo Pedaste) writes:
>
>>I have a noname VGA card (I think its called an ULTRA) which has clocks
>>25 28 32 and 36. Under X1.0 at 25MHz it produced a display about 1200x500,
>>under X1.1 I get a display about 600x500. This is presumably due to clock
>>doubling being turned on in X1.0 and turned off in X1.1.
>
>Could somebody say a bit more about clock doubling and all that? I
>found under 1.0 that I had to say "hiclock" to get my Cardinal 700
>card to work properly. I've tried all the hacks I can think of, and
>1.1 still needs hiclock. I have a feeling it would help for me
>to understand exactly what hiclock does and why.
ok. as far as i understand it (i don't have a hiclock board), here goes:
most et4000 boards have 8 clocks, in the range 25mhz - 70mhz or so. you
select them by entering 8 clocks in the Clocks line of Xconfig.
certain newer boards have more than 8 clocks, with frequencies about double
that of the original 8. since these new clocks are selected in the second
"bank" of clocks, the original x386 couldn't use them properly.
somone posted a hack called 'vendor "hiclock"' which would enable the et4000
chip to use the higher clocks, fooling x386 into thinking it was using a
slower speed. since the clocks line is strictly for the et4000 driver's
benefit, it didn't matter. this was the solution which was in place in
x11v1.0.
in the x386 1.2e release (the next great release of x386 with massive amounts
of assembler for performance), the problem was corrected by having the
et4000 driver detect 16 clocks rather than 8. this means the Clocks line
in your Xconfig needs to have some dummy values in the first 8 slots
before the next 8 real clock values appear. the 'vendor "hiclock"' hack
is gone, so using it doesn't do anything.
i hoped i had made this clear in the readme and people have replied that
the new method works like a charm. the only point is that you will have
to make modifications to your Xconfig, if you use the Clocks line, so
that the first 8 clocks are the "regular" values and the next 8 are those
of the higher frequencies. then you should be able to use it without trouble.
redirect the output of startx (the stderr output) to a file to see what
X386 thinks your board's clocks are (for this, comment out the Clocks line
in Xconfig) and use that as a starting point.
if someone has gotten the new form of hiclock handling to work and sees that
this is obviously incorrect please correct me!
zorst
[obz@raster.Kodak.COM]
-- zorst (orest zborowski) [obz@raster.kodak.com]