[rescue] SPARCstation 5: framebuffer resolution wont change

Romain Dolbeau romain at dolbeau.org
Sat Apr 1 12:02:55 CDT 2017

2017-04-01 18:25 GMT+02:00 Mouse <mouse at rodents-montreal.org>:
> Based on my own experience, I would suggest using an _older_ multisync,
> preferably a real CRT.

I would agree with that. My old Iiyama Vision Master Pro 410 (17" CRT)
can display pretty much anything you throw at it (and has BNC input in
addition to VGA).

That being said...

> I once spent an entire afternon trying to get a 1920x1080 flatscreen to
> display 1920x1080 from a SPARCstation-20, and failed.

TGX or SX ? TGX+ should be possible in some cases... (you need the 4
MiB of the + for the resolution, TGX won't do anything larger than the
default 1152x900 with just 1 MiB)

Most flatscreen won't sync to anything with a refresh rate not very
close to 60 Hz in practice. Specifications tend to be like 59-61 Hz,
58-62 if you're lucky. Unfortunately 1920x1080 @ 60 Hz already needs
more than 124 MHz of pixel bandwidth just for the visible area, and
the available 135 MHz clock in the TGX(+) is way too low to output an
usable signal @ 60 HZ. You might be able to get away with the 135 MHz
clock and a 55 Hz refresh on some LCD with something like:

: r1920x1080x55 " 135000000,61058,55,20,251,20,1920,6,6,18,1080,COLOR,0OFFSET" ;

But only the most accommodating hardware will work. And the 189 MHz
clock is way too high for most LCD to sync to, let alone the 216 MHz

The TGX(+) has a programmable clock, so with a lot of Forth voodoo you
can try programming other pixel clocks... I've managed to get
1600x1200 at 75 on my VMP410 CRT with a custom clock on a TGX+ and

: r1600x1200x75 "
202500000,93750,75,64,192,304,1600,1,3,46,1200,COLOR,0OFFSET" ;

and it was just fine on a SS5 running a very old Debian, complete with X11.

For flatscreen I would suggest older 17" 1280x1024, with a TGX+ and
standard clock, e.g.

( EDID resolution for the SyncMaster 713BM 1280x1024x60 ; work on it )
: r713bm " 108000000,63981,60,48,112,248,1280,1,3,38,1024,COLOR,0OFFSET" ;

You can also get VESA resolution from a TGX/TGX+ with custom clocks, e.g.:

( VESA 1024x768 @ 75 ; work on SM 713BM )
: r1024x768x75 " 78750000,60022,75,16,96,176,1024,1,3,28,768,COLOR,0OFFSET" ;

( VESA 800x600 @ 72  ; work on SM 713BM )
: r800x600x72 " 50000000,48076,72,56,120,64,800,37,6,23,600,COLOR,0OFFSET" ;

TGX(+) were amazing piece of hardware :-)


Romain Dolbeau

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