The xf86InitFBManager function in the
xc/programs/Xserver/hw/xfree86/common/xf86fbman.c file contains a sanity check
for input parameters that is always false. This is found in the following
if (FullBox->x2 < FullBox->x2) return FALSE;
As you can see, FullBox->x2 will always be equal to itself, so this check will
never evaluate to true and do the 'return FALSE'.
I think that the second FullBox->x2 in the conditional should be FullBox->x1
similar to what the previous line in the file does for the Y coordinate. See
the attached patch.
Created attachment 4828 [details] [review]