linuxconsole-dev

Re: Two accelerated xservers on a single G550

[Aivils S. <Aiv...@un...>]

> I stumbled across a XFree86 config file for the G450,
> which had something new to me.  There were two
> device sections referrring to the same BusID,
> but with screen=0 and screen=1.
>
> I decided to try the same on my G550.  Instead of
> running the second head with framebuffer, I used
> the mga accelerated driver and screen=1.
> The first attempt failed, X found "a suitable device
> but no screen" or some such.  So I removed
> the screen=1 thing just to see what happened.
>
> Accelerated mga was already running on the first head
> as :0, and I now started another accelerated server with
> the same configuration as :1, with another keyboard and mouse.
>
> It worked in a weird way - I got two xservers running on the
> _same_ screen.  Each mouse had its own cursor, they could
> chase each other around.  I opened one xterm with each
> mouse. My left keyboard worked with
> the left xterm, the right keyboard witht he right  xterm.
> A "poor man's ruby setup", dual seat with a single screen.

Congratulations! You open new "matrox psyho circus" thread.
IMHO with right config You solutions works. Of course any
cyberpunk may use neighbour display, but that by-product only.

Please test config, whrere both xf86 use _two_ screens without
xinerama. If You use both screens of matrox device, then You
can determine "who is who".
     1st xf86 "matrox device screen=0" as _fisrt_ xf86 Screen
in ServerLayout, but "matrox device screen=1" as second
     2nd xf86 swap order of "matrox device" in ServerLayout.
"matrox device screen=1" is _first_ for this server.

Both servers setup both screens, which one may work according
Your reports above. Because matrox device order is swaped, then
sys admin can determine where runs programs under each xf86.

"xterm -display :0.0" runs on owner display
"xterm -display :0.1" runs on neighbour display

But DISPLAY=":0.0" always.

You might add in .xinirc line
xsetroot -display :0.1 -color most-compatible-colour

This solution cannot be called "technical correct".

You can try patch program Xnest to use independ mouse
and keyboard.

Aivils Stoss

Re: Two accelerated xservers on a single G550

[Helge H. <hel...@ai...>]

Aivils Stoss wrote:
 
> Congratulations! You open new "matrox psyho circus" thread.

Does this imply there were an earlier matrox psycho
circus thread?  If so, is there a searchable archive somewhere?

> IMHO with right config You solutions works. Of course any
> cyberpunk may use neighbour display, but that by-product only.
> 
Well, the NAT box on my home network only lets ssh through,
so I don't worry too much about X security. 
But why would there be a problem?  The two X servers are independent
and each can enforce security on its own connections.  The only
security breach I can imagine is that one logged-in user
may read the other logged-in user's window contents because he
has access to the same framebuffer memory.  "Any cyberpunk" on the
net (or even logged-in but not running X) shouldn't be more
of a problem than with a ordinary setup?

Right now those xserves are insecure because they are dri-trunk servers
wich happens to have no security compiled in. But I don't need
that for the dual setup, it is only to get DRI.  

> Please test config, whrere both xf86 use _two_ screens without
> xinerama. If You use both screens of matrox device, then You
> can determine "who is who".
>      1st xf86 "matrox device screen=0" as _fisrt_ xf86 Screen
> in ServerLayout, but "matrox device screen=1" as second
>      2nd xf86 swap order of "matrox device" in ServerLayout.
> "matrox device screen=1" is _first_ for this server.
> 
Great idea!
Both users can stick to his/her "first" screen and simply not
use the second one (which only would stomp on the other users
display)

I guess only one user really need a setup with two displays, 
using the  first one as a "placeholder".  The user with the
first display can simply keep using that.

> Both servers setup both screens, which one may work according
> Your reports above. Because matrox device order is swaped, then
> sys admin can determine where runs programs under each xf86.
> 
> "xterm -display :0.0" runs on owner display
> "xterm -display :0.1" runs on neighbour display
> 
> But DISPLAY=":0.0" always.

I believe the first user will see his display as :0.0 and
the other user's display as :0.1?

And the other user will see his display as :1.0 and the
first user's display as :1.1?

One xserver start as :0 and the other as :1 with the
current single-screen setup.

> 
> You might add in .xinirc line
> xsetroot -display :0.1 -color most-compatible-colour
> 
> This solution cannot be called "technical correct".
The "correct" way would be to tell an xserver to use the 
second G550 display only.  I don't know if that is
possible to do though.

> You can try patch program Xnest to use independ mouse
> and keyboard.

I don't understand this.  Ruby already provides
independent keyboards.  And the two X servers have no
problem using independent mice.

From my /etc/X11/xdm/Xservers file:
:0 local /usr/X11R6/bin/X :0 vt17  -deferglyphs 16 -nolisten tcp
:1 local /usr/X11R6/bin/X :1 vt7 -deferglyphs 16 -nolisten tcp -xf86config xf86config-4

The vt7/vt17 decides the keyboard, :0/:1 sets display numbers. The first server uses
standard XF86Config-4 and the other uses the alternative xf86config-4.
The XF86Config-4 is unchanged from ordinary single-user setup,
using accelerated mga on the first display.
Contents of xf86config-4 varies depending on what I want to do.
It is usually set up for fbdev X on the second framebuffer device,
I also tried  letting it use the mga driver and got two servers
using the same screen.  Using the two-screen setup you mentioned will
be an interesting experiment.

Helge Hafting