why does -sharevts is so important for multseat setup?

[Aivils Štoss]

Citējot "StompDagger1 at yahoo.com" <stompdagger1 at yahoo.com>:

> Hello,
>
>
> I have a multiseat setup and where I'm experiencing lose of  
> keystrokes in the second seat.
> I'm using hotpluged (via udev) feature, what  I do noticed that if I  
> press CRTL+ALT+F1on seat 2, seat1 goes to cli.
> for now I'm putting udev aside on this matter and try to concentrate  
> on X part, while searching the web I've found a article that  
> mentions that such issue can happen due to the -sharevts.
>
> I wanted to know, why multiseat setup needs to share vts? why if I  
> take out this feature, one of the seats doesn't lights up?
>

Normally kernel sends key press events to applications via /dev/ttyXX  
device files. Each Xorg open single /dev/ttyXX file and receive  
keyboard events. /dev/ttyXX was designed to support single active  
application like Xorg. When one X became active then another  
suspended. So single end-user can easy switch between multiple X  
instances. Multiseat have another mission. That is a reason of  
-sharevts. Active X does not try to suspend another X via /dev/ttyXX.  
In reality /dev/ttyXX stay unused under multiseat, because every X  
receive events from keyboards via /dev/input/eventXX device files.

As alternative You can hack the Linux kernel with faketty (outdated) module.

Aivils Stoss