- * uses offset = 0 && length = RAMDAC register width.
- * var->{color}.offset is 0
- * var->{color}.length contains widht of DAC
+ * var->{color}.offset is 0 unless the palette index takes less than
+ * bits_per_pixel bits and is stored in the upper
+ * bits of the pixel value
+ * var->{color}.length is set so that 1 << length is the number of available
+ * palette entries