Re: SPARCStation VSIMM

[Malte Dehling <mdehling%gmail.com@localhost>]

Hi,

On Thu, Oct 28, 2021 at 03:19:55PM -0400, Mouse wrote:
> > With the 8MB VSIMM you can theoretically do 1920x1080 in 24bit.
> 
> No "theoretically" about it.  I run 24-bit-capable 1920x1080 routinely
> on the SS20 I have an 8M VSIMM in.  (I usually have fairly few 24-bit
> windows, because 8-bit is perceptibly faster, but I've done
> full-screen 24-bit windows; they work.  My other two live-service
> SS20s, one of which actually isn't very live at the moment, have 4M
> VSIMMs because I don't have enough 8M VISIMMs.)

Can you share what monitor and settings you use?  The 2.25(R) OBP has
only one 1920x1080 mode and it's 1920x1080@72Hz with a 216MHz pixel
clock.  I seem to remember that you use a different setting?  I've been
playing around with the settings on my SS20 with a 4MB VSIMM and an NEC
MultiSync EA241WMi, and I can get it to output 1600x1200@60 (162MHz) and
1920x1200@60 (193MHz), both in 8 bit, but haven't found a good setting
for 1920x1080.

> This _is_, though, with my cg14 ddx layer in the MIT X11-6.4p3 server.
> Depending on what you care about having in the server, that may or may
> not be good enough for your purposes.  I have no idea how hard it
> would be to do something of the sort in an Xorg server, though anyone
> who wants to look at adapting what I've done is certainly welcome to
> do so.

Is your code available somewhere?  I'd love to have a look at it!

The standard Xorg driver at the moment assumes 24 bit mode.  Trying to
run Xorg in, e.g., 1920x1200 (so 8 bit) will crash it.  Getting it to
work in unaccelerated mode is pretty easy (I managed to do it and I
really don't know what I'm doing here.)  I haven't managed to get
acceleration to work.

As an aside (I know this is a NetBSD list, but maybe some other people
are interested in historical UNIX system like me):  The Solaris kernel
driver keeps an internal table of video modes and tries to match
whatever setting is used to the table.  To match, horizontal and
vertical resolution as well as refresh rate have to be identical.  If no
match is found the driver will try to dereference a null pointer and
crash.  This issue can easily be fixed, e.g., with a hex editor.  I have
not been able to get the Xsun X server to work, however.

NEXTstep seems much better: while by default the installer will assume
24 bit mode for the CG14, after installation it can be set to 8 bit mode
and one can run NEXTstep in 1920x1200 with full acceleration.

(Both Solaris and NEXTstep work just fine in 1920x1200 in 8 bit mode
using a TGX+.)

Cheers,

-- 
Malte Dehling
<mdehling at gmail.com>