Flicker either BUG in SDL or HW

Ok… flickering when double buffer is either a bug in SDL or a bug in
my video card or somwhere. After spending 2 days trying to stop the flicker I
tried to find some other code that uses double buffering. The “testsprites” in
the test directory from the source distribution uses double buffering when ran
with the -flip and -fullscreen command line options. It did the same thing that
my program was doing. It flickered on and off really fast between the yellow
bouncing balls and a black screen. This is when running as root in X11 DGA. My
video card is a Voodoo3 3000. I am wondering how I can figure out where the bug
is, whether in my x server or in SDL. Also on another windows computer with a
matrox Millenium II on it double buffering does not work either. On this one it
seems that it is impossible to write to a seccond buffer, all writes go to
the same buffer. Flipping does work… It flips from what I have drawn
and a black screen but any draws Whether locked, unlocked, accessing the
buffers, or blitting or filling or anything go directly to one buffer no matter
how many times you flip. I don’t know if this is somehow related but there has
to be something wrong with doublebuffering somewhere. Has anyone else tried to
run “testsprites -flip -fullscreen” as root and has it worked???