Problem with flickering LCD on my iBook2.2

I'm trying to set up X on my iBook running -current. The problem is
that, I have some flickering horizontal lines running thru my screen
and some hickups of the LCD. The video card is a Radeon L7 Mobility
LW, and this problem occured too when I ran Linux. The only way to get
it clean was to add Option "UseFBDev" "true" to my card section in
XF86Config.
But this I cannot do on OpenBSD because fbdevhw module is missing.

I tried to go with wsfb, but no successes just bad crashes and
hangups.

Beside that, I had a good screen once, yesterday, when I decided to
upgraded to XF44 binaries provided by Matthieu Herrb, but it lasted
till the next reboot, and since then, no clean screen :-(

The config for my card I tried for wsfb is:

Section "Device"
        Identifier "card0"
        Option "PanelHeight" 768
        Option "PanelWidth" 1024
        Driver "wsfb"
        Option "device" "/dev/ttyC0"
EndSection

and with radeon module:

Section "Device"
        Identifier "card0"
        Driver "radeon"
        Option "UseFBDev" "true"
EndSection

Thanks for any suggestions.
Have a nice day.

-- 
Mathieu Segaud

"Quite frankly, I'd rather have a few people hate me deeply than apply
 stuff I don't like."

 	- Linus Torvalds