855GM and Max amount of VideoRAM

[Bob Koninckx]

Hello list,

We are working on a embedded board with an intel 855GM chipset. We  
need to drive a 1ever, 920x1200 monitor with this board. Our  
application relies heavily on Xv.

With the latest driver from intel, as well as with the one one in  
debian testing (xserver-xorg-video-intel) we arrive at driving the  
monitor in its native resolution. However, Xv only shows the colorkey  
(blue screen) instead of the video we want. At lower resolutions, Xv  
works ok, which makes me suspect a problem with the amount of  
allocated videoram.

The driver, automatically allocates 128M.

When looking at the driver code, I saw that this is the default value  
for this chip, and that it might be further decreased along the  
initailisation of the driver, depending, e.g on aperture size,  
available memory, etc.

Our board has plenty of memory, and BIOS allows an aperture size of 256M.

So, my question, is: is this 128M a limitation of the chipset, or is  
it just the driver ? Any suggestions, pointers to getting Xv working  
at a 1920x1200 resolution with the 855GM, or a confirmation that this  
is simply not possible, would be greatly appreciated.

For completeness, I also add the detection of the chip from the Xorg log

82852/855GM Integrated Graphics Device rev 2, Mem @ 0xf0000000/27,  
0xffa80000/19, I/O @ 0xec00

We are working with a 2.6.18 kernel

Thanks for any help,

Bob