Re: [Linux-fbdev-users] matroxfb - 2.4.26 - G450 dualhead -

[Petr V. <VAN...@vc...>]

On 21 Oct 04 at 14:28, Andreas Burmester wrote:
> 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 "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?

Are you sure you do not want 'laced true' and normal VGA resolution with
525 lines?  Just take your 31kHz resolution, multiply pixclock by 2 and
set laced to true.
 
> 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.

Which resolution you cannot set?  fb1 is more restrictive on line
length (must be multiple of 128 or something like that) and supports
only 16/32 bpp.  And it does not support interlaced picture for RGB
output.
                                                    Petr Vandrovec