How to find HorizSync / VertRefresh rates?

Tom Evans at
Mon Apr 30 17:09:00 UTC 2007

On Mon, 2007-04-30 at 11:02 +0200, Victor Engmark wrote:
> Hi all,
> I'm trying to create a pristine xorg.conf, but I've been unable to
> find proper values for HorizSync and VertRefresh for my Dell Latitude
> D610.

Don't bother trying. If it works when you leave them unspecified, don't
think any more about it.

If it still doesn't work however, the easiest way is to construct a
valid modeline specific to your monitor. Xorg can actually tell you what
to put into your xorg.conf, see section of the FreeBSD Handbook

The quickest way to get these values out is to grep your Xorg log (even
from a failed run of Xorg). Eg (quoting from the Handbook) :

$ grep -A 4 'Supported additional Video Mode' /var/log/Xorg.0.log
(II) I810(0): Supported additional Video Mode:
(II) I810(0): clock: 108.0 MHz   Image Size:  340 x 270 mm
(II) I810(0): h_active: 1280  h_sync: 1328  h_sync_end 1440 h_blank_end
1688 h_border: 0
(II) I810(0): v_active: 1024  v_sync: 1025  v_sync_end 1028 v_blanking:
1066 v_border: 0
(II) I810(0): Serial No: ETL5108015

This information is called EDID information. Creating a ModeLine from
this is just a matter of putting the numbers in the correct order:

ModeLine <name> <clock> <4 horiz. timings> <4 vert. timings>

Heres one I made earlier (unfortunately, not the one from the log, that
one works 'out-of-the-box')

ModeLine "1680x1050" 146.0 1680 1784 1960 2240 1050 1053 1059 1089



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