, "amiga-x <amiga-x@NetBSD.ORG>
From: Markus Illenseer <markus@tiger.teuto.de>
List: amiga-x
Date: 06/08/1995 23:54:12
Antti Miettinen wrote:
> The result with X11 has always been black screen.
This problem is known for long - many solutions been triend since then -
no success.
> I have tried the X servers Xamiga24, Xcl, Xamiga24-950305 and
> Xcl-950408.
Has nothing to do with the servers, but with the grf-device.
> The cirrus-3 package has comments that the Picasso has some kind of
> ZorroII to ISA translation which causes black screen problems. But why
> would this only be relevant with a 040?
Didn't I explain that in this doc? Hm. Timing problem and design error
in the 040 to Zorro interface of almost all 040 boards for A2000.
> It seems that I don't really
> understand what the comments are referring to as they claim that the
> problem could be solved by adding 0xffff to some register addresses.
> In my limited understanding this would only lead to accessing wrong
> addresses. The whole register block is 64k, isn't it?
Yes 64K, and by adding 0xfff (not 0xffff as stated in the doc) you will
get a byte-swapped address after it was passed through the 040 to Zorro
interface. Call that black magic :-)
> #if 1
> *(ba + 0x3c6) = 0xff;
> *(ba + 0x3c6);
> *(ba + 0x3c6);
> *(ba + 0x3c6);
> *(ba + 0x3c6);
> *(ba + 0x3c6) = 0xd0;
> #endif
>
> I was at least able to see something. Without those lines the screen
> remained white. So is this piece of code accessing the hidden DAC
> register, which is referred to in grf_clreg.h and why would this make
> any difference?
Interesting piece of code. Did you set "1" to something? Is the compiler
supposed to use the stuff inside the if-endif? For I believe a black
screen means: not initialized at all and a white screen: not initialized
correctly, you seem to be on the right trace.
> Are the sources for the various X servers available from somewhere?
You don't need them?!
--
Markus Illenseer