diff options
| -rw-r--r-- | drivers/video/skeletonfb.c | 8 | ||||
| -rw-r--r-- | drivers/video/vfb.c | 11 | ||||
| -rw-r--r-- | include/linux/fb.h | 8 |
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 */ |