The multi-monitor situation
<michael@i3wm.org>
-July 2012 +April 2013
â¦or: oh no, I have an nVidia graphics card!
Please upgrade your nVidia driver to version 302.17 or newer and i3 will just +work. This document is kept around for historic reasons only.
1. The quick fix
If you are using the nVidia binary graphics driver (also known as blob) -you need to upgrade to at least version 302.17 (released in June 2012).
In case you cannot update the driver to 302.17 or newer on your machine for -some reason, use the --force-xinerama flag (in your .xsession) when starting -i3, like so:
2. The explanation
Starting with version 3.ε (March 2010), i3 uses the RandR (Rotate and Resize) -API instead of Xinerama. The reason for this, is that RandR provides more -information about your outputs and connected screens than Xinerama does. To be -specific, the code which handled on-the-fly screen reconfiguration (meaning -without restarting the X server) was a very messy heuristic and most of the -time did not work correctly — that is just not possible with the little -information Xinerama offers (just a list of screen resolutions, no identifiers -for the screens or any additional information). Xinerama simply was not -designed for dynamic configuration.
Starting with version 3.ε, i3 uses the RandR (Rotate and Resize) API instead +of Xinerama. The reason for this, is that RandR provides more information +about your outputs and connected screens than Xinerama does. To be specific, +the code which handled on-the-fly screen reconfiguration (meaning without +restarting the X server) was a very messy heuristic and most of the time did +not work correctly — that is just not possible with the little information +Xinerama offers (just a list of screen resolutions, no identifiers for the +screens or any additional information). Xinerama simply was not designed +for dynamic configuration.
So RandR came along, as a more powerful alternative (RandR 1.2 to be specific). It offers all of Xineramaâs possibilities and lots more. Using the RandR API made our code much more robust and clean. Also, you can now reliably assign @@ -77,16 +77,17 @@ workspaces to output names instead of some rather unreliable screen identifier (position inside the list of screens, which could change, and so onâ¦).
As RandR has been around for about three years as of this writing, it seemed like a very good idea to us, and it still is a very good one. What we did not -expect, however, was the nVidia binary driver. It did not support RandR until -mid 2012, even though nVidia had announced that it will support RandR -previously. What does missing RandR support mean for you? First of all, you are -stuck with TwinView and cannot use xrandr. While this ruins the user -experience, the more grave problem is that the nVidia driver not only does not -support dynamic configuration using RandR, it also does not expose correct -multi-monitor information via the RandR API. So, in some setups, i3 will not -find any screens; in others, it will find one large screen which actually -contains both of your physical screens (but it will not know that these are two -screens).
For this very reason, we decided to implement the following workaround: As long as the nVidia driver does not support RandR, an option called --force-xinerama is available in i3 (alternatively, you can use the