480x234 resolution with MediaGX card

Hi,

I have a SBC with a MediaGX graphics card. I run Redhat 6.2 on it. My
application is written using Qt embedded.

I can select modes from the fb.modes file (Mach64 ATI).

I want to drive an LCD display and need to change the resolution to
480x234.

How to I calculate (tune) the timings for that resolution?

When I try to change the geometry to anything different than standard video
modes I get the following error:
Cannot Support Requested CRTMode 480x234 8 (39722, 60), 3
ioctl FBIOPUT_VSCREENINFO: Invalid argument.

This is an example from the fb.modes file:

#     640x480, 60 Hz, Non-Interlaced (25.175 MHz dotclock)
#
#                       Horizontal  Vertical
#     Resolution        640         480
#     Scan Frequency          31.469 kHz  59.94 Hz
#     Sync Width        3.813 us    0.064 ms
#                       12 chars    2 lines
#     Front Porch       0.636 us    0.318  ms
#                       2 chars           10 lines
#     Back Porch        1.907 us    1.048  ms
#                       6 chars           33 lines
#     Active Time       25.422 us   15.253 ms
#                       80 chars    480 lines
#     Blank Time        6.356 us    1.430 ms
#                       20 chars    45 lines
#     Polarity          negative    negative
#

mode "640x480-60"
    # D: 25.175 MHz, H: 31.469 kHz, V: 59.94 Hz
    geometry 640 480 640 480 8
    timings 39722 48 16 33 10 96 2
endmode


Thank you for your help.


Wilhelm Leichtfried
[email protected]





-------------------------------------------------------
This sf.net email is sponsored by: Jabber - The world's fastest growing 
real-time communications platform! Don't just IM. Build it in! 
http://www.jabber.com/osdn/xim