The first 3 parameters of this sub-option should be obvious: <xres>,
<yres> and <depth> give the dimensions of the screen and the number of
-planes (depth). The depth is is the logarithm to base 2 of the number
+planes (depth). The depth is the logarithm to base 2 of the number
of colors possible. (Or, the other way round: The number of colors is
2^depth).