On Fri, 20 Feb 1998 15:06:55 -0700  Michael L. Hitch wrote:

> On Feb  1, 11:53am, James Alexander Jacocks wrote:
> > I have a DECStation 5000/120 32/1gb with CDROM.  I have a PMAGB-BA
> > framebuffer.  As I have come to understand it, the PMAGB-BA that I have
> > actually has the second oscillator that would normally be installed on a
> > PMAGB-BC.  Whenever I try to boot any version of NetBSD, the display goes
> > haywire.  (I.e. everything goes interlaced and moves slowly off the
> > screen)  I can read (sortof) the output enough to see that NetBSD is
> > actully booting, so the system doesn't crash.  However, it is _extremely_
> > difficult to use without the console. :)
> > 
> > I haven't tried the 1.3_release kernel, but I tried 1.2g and all the beta
> > kernels, and so for, no luck.  Any ideas?
> 
>   I had a chance this week to play with a PMAGB-BA that has two crystal
> oscillators.  I was trying to get it to work with a 17" monitor I have
> at home.  With the jumper removed, the board uses the higher frequency
> oscillator, and gives a display of 1280x1024 - which didn't work with
> my monitor.  On a whim, I added the jumper which appears to use the second
> oscillator, and that resulted in a 1024x786 display which worked with my
> monitor - until NetBSD booted anyway.  NetBSD assumes that the PMAGB board
> is 1280x1024, which will not work correctly when the PMAGB is using the
> slower oscillator.
> 
>   I modified the sfb.c driver to use 1024x768 and was able to get NetBSD
> to boot using that resolution.  The trick now is to have the driver detect
> what resolution the PMAGB is actually using and automatically set the
> appropriate display parameters.  From the sfbreg.h file, I do see a couple
> of registers on the PMAGB that seem to have something to do with the
> horizontal and vertical configuration, but I don't know what the values
> of those registers really mean.

Just a hunch, but do the register values correspond to what a "cnfg
<slot>" shows?  The PMAGB is about the most "verbose" card I've seen
when it comes to the cnfg command.  I can dig up what each frequency
(1024x864 and 1280x1024) returns later on today.  (Are you sure you're
seeing 768 lines and not 864 lines?).

Simon.