On Feb 22,  3:39pm, Simon Burge wrote:
> On Fri, 20 Feb 1998 15:06:55 -0700  Michael L. Hitch wrote:
> >   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?).

  Quite sure [VHORIZONTAL and VVERTICAL are the sfb registers]:

sfb0 at tc0 slot 0 offset 0x0
XXX VHORIZONTAL 4080900 VVERTICAL 5860b00
 (1024x768x8)tc_intr_establish: slot 0 level 0 handler 0x8011d600 sc 0xc0401900 on

cnfg 0
 0: PMAGB-BA DEC      V1.1     TCF0  (HX -- d=8 )
        -------------------------------------------------------
        Video Ram Size          2097152 
        Number of Planes        8 
        Character Rows          51 
        Character Columns       128 
        Crystal Selected (Mhz)  74 
        Refresh  Rate (Hz)      72 
        Vertical Scanlines      768 
        Vertical Front Porch    1 
        Vertical Back Porch     22 
        Vertical Sync           6 
        Horizontal pixels       1024 
        Horizontal front porch  16 
        Horizontal back porch   128 
        Horizontal Sync         128 
        Refresh Count           291 
        Cursor X                232 
        Cursor Y                27 
        Video Base Address      0x1000 
        -------------------------------------------------------


sfb0 at tc0 slot 0 offset 0x0
XXX VHORIZONTAL 74a1140 VVERTICAL 8831c00
 (1024x768x8)tc_intr_establish: slot 0 level 0 handler 0x8011d600 sc 0xc0401900 on

cnfg 0
 0: PMAGB-BA DEC      V1.1     TCF0  (HX -- d=8 )
        -------------------------------------------------------
        Video Ram Size          2097152 
        Number of Planes        8 
        Character Rows          68 
        Character Columns       160 
        Crystal Selected (Mhz)  130 
        Refresh  Rate (Hz)      72 
        Vertical Scanlines      1024 
        Vertical Front Porch    3 
        Vertical Back Porch     34 
        Vertical Sync           3 
        Horizontal pixels       1280 
        Horizontal front porch  32 
        Horizontal back porch   232 
        Horizontal Sync         160 
        Refresh Count           468 
        Cursor X                368 
        Cursor Y                38 
        Video Base Address      0x1000 
        -------------------------------------------------------


-- 
Michael L. Hitch			mhitch@montana.edu
Computer Consultant
Information Technology Center
Montana State University	Bozeman, MT	USA