matroxfb - 2.4.26 - G450 dualhead - 15khz resolution?

I'm trying to get my Matrox G450 dualhead to supply two fb consoles,
one (fb1) at normal resolution (31khz) to my normal screen, and one
(fb0) at old arcade resolution (15khz) to my arcade machine.

As a bridge between my G450 and arcade machine, I have a JPAC
(http://www.ultimarc.com/jpac.html), which verifies the resolution and
amplifies the video signal. The JPAC has 3 LEDs indicating the input
resolution, 31khz, 25khz and 15khz.

I have specified two fbmodes, one 15khz and one 31khz.

mode "31khz"
  # D: 25.176 MHz, H: 31.469 kHz, V: 59.942 Hz
  geometry 640 480 640 13100 16
  timings 39721 40 24 32 11 96 2
endmode

mode "15khz"
# D: 5.544 MHz, H: 15.750 kHz, V: 60.115 Hz
geometry 256 240 256 480 16
timings 180375 32 32 16 3 32 3
accel false
endmode

The problem is when I set the 15khz mode on fb0 (connected to the
JPAC) non of the LEDs is on. If I set the 31khz mode on fb0, the 31khz
LED is on. Could it be possible that the fbset indicates 15khz, but is
not actually outputting it?

Another thing, is that I set much flexible resolutions on fb0 then
fb1, how come is that? ie. I can't set the 15khz mode on fb1.

Thanks for any help.
-Andreas


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