On Fri, 21 Nov 1997 13:06:23 -0800  Jonathan Stone wrote:

> James Alexander Jacocks <silence@wam.umd.edu> writes:
> 
> >I have a DecStation 5000/120 24mb and am having an interesting seemingly
> >video-related problem when trying to boot a netbsd kernel.
> 
> >No matter which kernel I try (1.3, or 1.2), as soon as the kernel is
> >recognized, and the sizes displayed, the screen seemingly becomes
> >interlaced, and the text on the screen bounces up the screen back and
> >forth.  Eventually, I get a prompt of some sort, but, due to the video
> >situation, I am unable to read it.
> >
> >Here is my sysconfig:
> >
> >DecStation 5000/120
> >24mb Ram (6x4mb modules)
> >PMAGB-BA frame buffer
> >19" Dec color monitor (the big big heavy one)
> >RZ23L (rz0)
> >Iomega Jaz (rz4)
> >
> >I currently have parts of Ultrix 4.4 on the rz23, and that boots and runs
> >fine...
> >
> >Any help/suggestions as to what I have done wrong would be appreciated.
> 
> Hi,
> 
> If Ultrix boots on this machine, and it uses the graphics monitor as
> system console, and NetBSD doesn't, you're probably not doing anything
> wrong.  I do wonder about the monitor, though.  it sounds like the video
> frequency from the card doesn't match the fixed-frequency monitor.
> Other people have run NetBSD 1.2 and 1.3ALPHA on SFBs, so I'm guessing
> it's something about your hardware.
> 
> Can you get the model number (like VR-2xx, or VR19) from the back of
> the monitor and post it? and also the output of
> 
> 	>> cnfg
> 
> with the model number and any version/submodel info of the PMAGB-BA?
> (>> cnfg N, where N is the slot with the sfb, might have more info.)
> 
> I seem to remember that the SFB actually comes in two varieties, which
> run at different video rates (60 and 66 Hz, or possibly 66 and 72).
> But the driver in NetBSD only seems to use one speed. Perhaps you have
> a monitor/card combination that Ultrix supports but NetBSD doesn't?
> 
> If so, it should be straightforward to fix, if we can figure out
> the (sub)model info or card jumpers properly.

We've also got a number of SFBs here with an extra 60 something MHz
crystal so that they can drive monitors like VR297s at 1024x864 (you
select between the two crystals with a jumper).  I think the "offical"
part number for one of these is a PMAGB-BC, but we just modified the
PMAGB-BAs ourselves.  Maybe that could be a problem too.  This is where
the `>> cnfg N' will help greatly - the SFB spits out all sorts of info
when queried.

I _think_ that PMAGB-BBs could drive 72 & 66 Hz, and PMAGB-BDs could
drive 72 & 60 Hz.  This is stretching the memory somewhat!

Simon.