Re: Multiple Keyboards in 2.2/2.4?

From: James Simmons (jsimmons@acsu.buffalo.edu)
Date: Thu Sep 07 2000 - 09:00:05 EST


> Is it / will it be possible to run multiple, or at least two keyboards
> before the new linux console code in 2.5?

XFree86 can use multiple keybaords. I don't think XF4.0 still supports USB
keyboards. Give them another 6 months or a year. By then they should
support them. As for the console system not it can't use multiple
keybaords. You can use multiple keybaords via the /dev/event interface.

> What we would like to do is to run multiple user sessions off a single
> machine. Using either Dualhead graphics cards, or simply using two
> graphics cards, the display is not a problem (although console support
> would be nice we only really need X), and multiple mice is not a problem
> with either two USB mice or one USB and one PS/2. However, there does not
> seem to be a way to address a second keyboard seperately at the moment.
> Looking at the linux console project the multi-head code "ruby" seems to
> be aimed at 2.5. I was wondering if there is any chance of being able to
> address keyboards before then?
>
> Nick
>
> Ie. Given that displays and mice almost work, we think it would be really
> cool to have two people work from a single box. AFAIK keyboard is the only
> issue stopping this...

    It is a whole lot more complex than that. Its possible with XF4.0 but
only with very limited hardware. The reason for it being on the console
level is so the kernel can manage the resources between different
applications. Consider a multihead enviroment with 2 users. Each VT is in
console mode. One starts the X server. Automatically X wants to set each
video card into graphics mode. Now if I was say writing code on that
second VT and all the sudden X started I would be really upset. Now
consider a "good" X server (not XFree86) that starts and doesn't affect
me. What happens when I start a X server on my VT? What impact will it
have on the other user. This things have to be considered.
    On the console level their are complex issues as well. Consider a
system with 4 VTs attached to one machine. What if one person pressed
Ctrl-Alt-Del. Anyone can bring the system down when multiple people depend
on it. This is bad. I could go on with other issues but will not bore you
with them.

MS: (n) 1. A debilitating and surprisingly widespread affliction that
renders the sufferer barely able to perform the simplest task. 2. A disease.

James Simmons [jsimmons@linux-fbdev.org] ____/|
fbdev/console/gfx developer \ o.O|
http://www.linux-fbdev.org =(_)=
http://linuxgfx.sourceforge.net U
http://linuxconsole.sourceforge.net

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