geometry < xres > < yres > < vxres > < vyres > < depth >
timings < pixclock > < left > < right > < upper > < lower > < hslen > < vslen >
options < value >

xres

visible horizontal resolution (in pixels)

yres

visible vertical resolution (in pixels)

vxres

virtual horizontal resolution (in pixels)

vyres

virtual vertical resolution (in pixels)

depth

display depth (in bits per pixel)

pixclock

length of one pixel (in picoseconds)

left

left margin (in pixels)

right

right margin (in pixels)

upper

upper margin (in pixel lines)

lower

lower margin (in pixel lines)

hslen

horizontal sync length (in pixels)

vslen

vertical sync length (in pixel lines)

the first value of this options is the default

hsync " {" low | high }

the horizontal sync polarity

vsync " {" low | high }

the vertical sync polarity

csync " {" low | high }

the composite sync polarity

extsync " {" false | true }

enable or disable external resync. If enabled the sync timings are not generated by the frame buffer device and must be provided externally instead. Note that this option may not be supported by every frame buffer device

laced " {" false | true }

enable or disable interlace. If enabled the display will be split in two frames, each frame contains only even and odd lines respectively. These two frames will be displayed alternating, this way twice the lines can be displayed and the vertical frequency for monitor stays the same, but the visible vertical frequency gets halved

double " {" false | true }

enable or disable doublescan. If enabled every line will be displayed twice and this way the horizontal frequency can easily be doubled, so that the same resolution can be displayed on different monitors, even if the horizontal frequency specification differs. Note that this option may not be supported by every frame buffer device

1 t left margin
2 t xres
3 t right margin
4 t horizontal sync len
5 t upper margin
6 t yres
7 t lower margin
8 t vertical sync len

htotal = left + xres + right + hslen
vtotal = upper + yres + lower + vslen

line = pixclock * htotal

hfreq = 1E12 / line = 1E12 / (pixclock * htotal)

if (lace) vtotal /= 2
if (double) vtotal *= 2

frame = vtotal * line

vfreq = 1E12 / frame = hfreq / vtotal