Azimout's Linux weblog


with 3 comments

xdpyinfo is a utility that displays info about your X configuration. to get your X server’s DPI, run xdpyinfo | grep resolution. instead, to get Gnome’s DPI value, run gconftool-2 --get /desktop/gnome/font_rendering/dpi

on my machine, it correctly displays the screen resolution, while the DPI (dots-per-inch) value is wrong (96×96 dpi), which also leads to wrong values for the actual screen dimensions… (actually, i’m not sure which value is calculated from which)

the way to change the X DPI setting is to run xrandr --dpi <dpi>

in my case the resolution is 1024×768 while the screen is 285x214mm, or 11.22×8.42 inches => the correct DPI settings for my machine (for this resolution) is 91×91 dpi

The display reports its capabilities to the graphics controller over the I2C bus using the Extended Display Identification Data (EDID) protocol (EDID + I2C = Display Data Channel (DDC)). This info can be read through sudo get-edid (you need to install the read-edid package, homepage here, which is at 1.4.1 since 2001), or one can run sudo ddcprobe (install the xresprobe package) to get a list of available standard resolutions.

Related bugs:


Written by azimout

27/12/2008 at 11:47

Posted in Problems

3 Responses

Subscribe to comments with RSS.

  1. The new read-edid can be found here:


    30/01/2009 at 13:26

  2. packaging request for read-edid 2.0.0 (with a new maintainer) in ubuntu:


    31/01/2009 at 11:31

  3. […] 1.6, which should fix the dpi issue i mentioned […]

    jaunty « Azitech

    16/03/2009 at 14:30

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: