3 files changed, 18 insertions, 9 deletions

diff --git a/drivers/video/skeletonfb.c b/drivers/video/skeletonfb.c
index a439159204a8..89158bc71da2 100644
--- a/drivers/video/skeletonfb.c
+++ b/drivers/video/skeletonfb.c
@@ -308,9 +308,11 @@ static int xxxfb_setcolreg(unsigned regno, unsigned red, unsigned green,
      *   color depth = SUM(var->{color}.length)
      *
      * Pseudocolor:
-     *    var->{color}.offset is 0
-     *    var->{color}.length contains width of DAC or the number of unique
-     *                        colors available (color depth)
+     *    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
      *    pseudo_palette is not used
      *    RAMDAC[X] is programmed to (red, green, blue)
      *    color depth = var->{color}.length
diff --git a/drivers/video/vfb.c b/drivers/video/vfb.c
index cc919ae46571..050d432c7d95 100644
--- a/drivers/video/vfb.c
+++ b/drivers/video/vfb.c
@@ -318,13 +318,16 @@ static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
          *   {hardwarespecific} contains width of RAMDAC
          *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
          *   RAMDAC[X] is programmed to (red, green, blue)
-         * 
+         *
          * Pseudocolor:
-         *    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
          *    cmap is not used
          *    RAMDAC[X] is programmed to (red, green, blue)
+         *
          * Truecolor:
          *    does not use DAC. Usually 3 are present.
          *    var->{color}.offset contains start of bitfield
diff --git a/include/linux/fb.h b/include/linux/fb.h
index f563c5013932..330c4b1bfcaa 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -173,8 +173,12 @@ struct fb_fix_screeninfo {
 /* Interpretation of offset for color fields: All offsets are from the right,
  * inside a "pixel" value, which is exactly 'bits_per_pixel' wide (means: you
  * can use the offset as right argument to <<). A pixel afterwards is a bit
- * stream and is written to video memory as that unmodified. This implies
- * big-endian byte order if bits_per_pixel is greater than 8.
+ * stream and is written to video memory as that unmodified.
+ *
+ * For pseudocolor: offset and length should be the same for all color
+ * components. Offset specifies the position of the least significant bit
+ * of the pallette index in a pixel value. Length indicates the number
+ * of available palette entries (i.e. # of entries = 1 << length).
  */
 struct fb_bitfield {
         __u32 offset;                   /* beginning of bitfield        */