Bug#268432: It has something to do with the color depth...
I checked the configuration of my woody xserver-s3 (which has version 3.3.6,
of course, not 3.6 as I told you) and discovered that I use only a color
depth of 16 there. So the configuration of xserver-xfree86 4.3.0 was not so
close to my woody configuration as I suggested. Sorry.
When I change the depth to 24 under woody, xserver-s3 shows me "No valid modes
found.". So obviously the lack of suitable 24 bit color depth modes leads to
the problem with sarge's xserver-xfree86. I changed the color depth to 16
under sarge and it worked.
Here is a complete overview of the results when trying the two different X
servers with the color depths 16 and 24:
xserver-s3, version 3.3.6 (woody) with color depth 16:
xserver-s3, version 3.3.6 (woody) with color depth 24:
shows "No valid modes found."
xserver-xfree86, version 4.3.0 (sarge) with color depth 16:
xserver-xfree86, version 4.3.0 (sarge) with color depth 24:
sends monitor to powersave mode (or chooses a video mode, the monitor
I would say, of course, that xserver-xfree86 4.3.0 should also give an error
message instead of sending the monitor asleep. ;-)