radeon page flipping fixed BUT ...

[Benjamin Herrenschmidt]

I found the problem I introduced with Page Flipping, I pushed a fix to
CVS, however, I still see a (different) issue. I don't think it was
introduced by my patch but I don't have an old X to test with at the
moment...

When using Page Flipping, I launch glxgears, it's all fine.

Now I move the window around, the content heavily flickers, alternating
between the gears and a black content.

When I "drop" the window (stop moving it), it will either be the gears
running happily ... or the black content. In that later case, it will
stay black until I move the window again and drop it at the right time
to get the gears back.

I don't know much about what's going on with DRI when moving windows
around so I would appreciate if somebody more familiar with that stuff
could help me figure that one out.

Ben.