Hi all. I'm new to UBUNTU as I've just installed it last weekend but I'm having trouble using my ATI Radeon HD3870 based graphics card in 16-bit color mode. The fglrx drivers don't support 16-bit color so I'm using the "radeon" open source driver.

Everything works fine in 24-bit color mode but if I add the line "DefaultDepth 16" to the xorg.conf file, then the window system develops a blue background. If I run xgamma from the terminal window to change the gamma values, adjustments to red or green make a change (but rgamma or ggamma above 2.0 make the image too bright), but changing -bgamma has no effect whatsoever on the image (whether I set -bgamma to 0.1 or 9.0, for instance).

Is this a normal problem to have? Is there any ideas on how I can resolve it?

Here is an excerpt of my xorg.conf file:

" Identifier "Card0"
Driver "radeon"
VendorName "ATI Technologies Inc"
BoardName "Radeon HD 3870"
BusID "PCI:1:0:0"
EndSection

Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
SubSection "Display"
Viewport 0 0
Depth 1
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 4
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 8
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 15
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 16
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
DefaultDepth 16
EndSection"