Subject: Re: Interlace and Retina
To: Greg Oster <>
From: Andy Heffernan <>
List: amiga-x
Date: 10/20/1994 08:12:38
> Michael Alan Hobart writes:
> > 
> > 
> > I also have had problems with interlace and the Retina Z2 board.  I would guess
> > that this is a glitch in how the driver was programmed.  I use an NEC Multisync
> > 3D monitor myself.  About the farthest I've been able to get it is 1000x750 but
> > the refresh rate here is down to 47 Hz.  This is only margal - i.e. it depends
> > on my mood and how tired I am whether it's too flickery or not.
> > 
> > It would be useful if someone would address the interlace programming issue.

Bill Coldwell also noticed this some time ago.  At the time, I looked
at the init code (swiped from the kernel), and couldn't see anything
obviously wrong.  But then, I couldn't see much that was obviously
right, either -- I'm not entirely sure what you have to do to the
Retina card to kick it into interlace.

> Hmm... I havn't seen this problem with my Retina Z2, and I've run it
> in 1280x1024 interlaced...  (I've got a ADI Microscan 4G for a
> monitor).  Horizontal 53.8 KHz, and 100 Hz vertical... Actually
> flickers less than 1280x1024 non-interlaced at 53.8 KHz horizontal and
> 50 Hz vertical.
> The only "problem" I've seen with the Retina is horizontal white lines
> about 150-200 pixels in length which "flash" to the left of the xterms
> when doing scrolling (they flash only along the left edge of the
> xterm).  I've only seen this problem at resolutions above 1024x768ni
> (1024x768ni is rock solid).  1152x900ni and 1192x900ni show this 
> "strange flashing" problem.. (I'm not sure how else to describe it :-(  ) 

Yes, I see this problem, too, except I see the flashes over on the
right hand side of the screen (I think maybe in the vertical strip
between 1024 and 1280).  I have satisfied myself that it isn't the code
that's doing this, at least not directly by drawing random lines during
the block-copy code.

The other problem I see with 1280x1024 appears when I display a GIF or
JPEG with xv.  If there are lots of colors, my monitor starts shearing
10-20 line groups on the display (hard to describe, but it looks like
the monitor is starting to flip out).  After a while, color registers
start getting trashed, so colors start dropping out.

The only conclusion that I've been able to come to is that the Retina
hardware just can't handle 1280x1024 without some difficulties.