Comment 49 for bug 144322

Like the topic starter, I ran into same problem trying to get RGB output from VGA connector in PAL timings (15625Hz horizontal 50Hz vertical interlaced):

When this error occurs, my CRT OSD displays 100Hz as the vertical frequency (should be 50)! Also, hooking up an oscilloscope to VGA Vertical output confirms this 100Hz frequency.

I think I can explain the screen as described by topic starter: The black horizontal border in the middle of the screen is just the extra Vsync pulse. After this extra Vsync pulse the vertical counters are reset, and the top half of the screen is repeated in lower half.

====>>>Workaround to get interlaced PAL output using 6.7.196
At latest geexbox developer version , xorg has DRI stuff included and I no longer managed to compile 6.6.3 in it:-(
However, I stumbled on a workaround:
1) Start Xorg using PAL interlaced setting. RGB output is like reported bug
2) use
xrandr -display :0.0 -s 1
to switch to different (also PAL interlaced) setting. Now RGB output is OK !
Even switching back to startup config using xrandr -display :0.0 -s 0 , PAL output is valid!

I have these lines in my xorg.conf
HorizSync 15-16
VertRefresh 49-51
Modeline "PALWS" 24.75 1280 1321 1437 1584 576 580 585 625 -hsync -vsync interlace
Modeline "PAL" 22.50 1152 1195 1301 1440 576 580 583 625 -hsync -vsync interlace

Intention of these 2 PAL modelines: My vga to scart convertor uses vertical sync length (note 585 and 583 in Vertical part of modeline) to switch the scart 16:9 pin.