why does -sharevts is so important for multseat setup?

[StompDagger1@yahoo.com]

From: Alexandre CONFIANT-LATOUR <alex at user-unfriendly.net>

To: "StompDagger1 at yahoo.com" <stompdagger1 at yahoo.com> 
Cc: "xorg at lists.x.org" <xorg at lists.x.org> 
Sent: Monday, August 20, 2012 11:25 AM
Subject: Re: why does -sharevts is so important for multseat setup?
 
Hello.

On 18/08/2012 20:05, StompDagger1 at yahoo.com wrote:
> I'm using hotpluged (via udev) feature, what I do noticed that if I
> press CRTL+ALT+F1on seat 2, seat1 goes to cli.

I dont know if that could help you but it seems to be a VT-Switch related problem. When you hit Ctrl-Alt-FX, a signal (SIGUSR1) is sent to X.org. This signal raise a flag that is handled by xf86Wakeup then xf86VTSwitch. This functions disable IO and framebuffer access for all screens. Then, an ioctl is sent to switch to cli.

I'm not familiar with multiseat, but this situation seems normal if your two seats share the same X instance. If not, it is a bit weird that the second X instance got notified.

On 18/08/2012 20:05, StompDagger1 at yahoo.com wrote:
> 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?

I think that -sharevts is used to allows multiple X instances to share the same /dev/ttyx but i may be wrong or it can have other uses.

-- Alexandre Confiant-Latour
@         : alex at user-unfriendly.net
Jabber    : choukette at im.apinc.org
GPG Key ID: 0x18CA62CC (pgp.mit.edu)

Hello,

Thanks for the replay,

I'm running X for each seat, meaning that any Ctrl-Alt-FX on a seat should not be passed to the other seat.
in my case, the signal is passed only to the other seat, not even to the origin seat.
why would multiple X instances to share the same /dev/ttyx? what is the gain in that?
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