Very Computer

Does anybody out there in net-land know if LINUX supports multiple
Monitors/Videocard combinations?

At work I play on a few HP systems with two headed displays and would like
to see if it is possible to obtain the same result from my x86 Pentium
with the addition of a second video card/monitor.

Any help would be great. Pointers to other sources, etc..

Thanks in advance.

Dave

PS: even saying weather you think this is possible or not would be a help.

There was a patch to run hercules-mono (in text) along with a VGA.
The hardware certainly supports this as I've used PCs with this
configuration under win3.1, it's actually quite handy to keep a
DOS shell open on the herc screen, while mousing around on the VGA.

The patch was for the 1.2.13 kernel. Never tried it myself. Best bet
is to browse through sunsite and probably post a query in the
developer ng.  

Also, as others may have suggested, you could opt for a vt100 terminal
plugged into your spare com port. You company probably has a spare
terminal just laying around. That would leave the VGA for X, etc.

Regards,
--------
Mark B.
Tucson, AZ

: : Does anybody out there in net-land know if LINUX supports multiple
: : Monitors/Videocard combinations?

My understanding of the situation is that the kernel needs a patch
(multimon) to allow the use of more than one screen, and that XFree does
not support more than one X screen.  Commercial X servers supposedly do
support multiple screens.

: Some questions I have are:
: 1) Will the x86 motherboards/BIOS allow for more than one video card without
: dying a terrible (yet not really fatal death)?

PCI should allow the use of as many video cards as slots, so long as the
cards can negotiate separate linear buffers.  This is my understanding of
PCI technology anyway.  You might also be able to toss in an ISA VGA in
the usual memory spot and a stone age herc, maybe for a total of five
monitors on modern PCI boards.  I don't think anyone has done this.

--
--
William Burrow  --  Fredericton Area Network, New Brunswick, Canada
Copyright 1997 William Burrow  
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And the one below it.

Quote:> Some questions I have are:
> 1) Will the x86 motherboards/BIOS allow for more than one video card without
> dying a terrible (yet not really fatal death)?
> 2) If the BIOS/motherborad will allow this, isn't it only a matter of starting
> two X-servers; one for each video card/monitor combination?
> 3) Is there such a setting for video cards that lets them know that they are a
> 'secondary' display device?
> 4) Should I necessarily have two cards that are the same (ie: two ATI mach 64
> video cards)?

In any case you really DON'T what it!  320x200 resolution is awful, and
Hercules cannot handle more.

--

[Sorry this is not threaded properly-- original thread disappeared]

monotors for X.

I'm not an expert but I can fill you in on some of the basics:

The PCI bus allows more than one video card to coexist without conflicts,
but I am not aware of any drivers for linux/X that support this. Under
MSWindows you can only have one video driver, and it comes from the video
card's manufacturer, and they're not going to support their competitors'
cards :-) so in that case the cards would have to be identical (the Matrox
Millenium is often mentioned for doing this under Windows). This
limitation wouldn't apply to linux, but if you have to modify the drivers
yourself it would probably make things easier. You might also have to
modify the X server.

You can get special video cards with more than one VGA chipset on them.
They come with drivers for Windows, but I've never heard of any drivers
for linux/X. Brands that have been mentioned in the past include STB,
Colorgraphics, Appian Graphics, and Tridium Research. It would be
interesting to know if any of these manufactureres would be willing to
release enough information to allow someone else to write a driver.

There is a program called x2x that allows the keyboard and mouse from one
X display to control another X display (eg, the console plus an X
terninal).  See ftp://gatekeeper.dec.com/pub/DEC/SRC/x2x/x2x-1.24.tar.gz
This sounds like the easiest solution to me.

You can use an old Hercules mono card but there are a couple of problems
with this approach. First, all the ones I've seen are 8 bit cards, and if
I understand this correctly, the VGA card also has to be used in 8 bit
mode, which tends to slow things down. Many of the clone mono cards also
emulate CGA (as grayscale) and this would conflict with the VGA card. I'm
not sure what happens if the VGA card is on the PCI bus.

The "Metro X" server will support a multi head system but only
with a Matrox video card.  Forgot tier URL but redhat.com has
a link to Metro.  Metro claims they will support other cards
later.

   I believe Xinside's X server for linux supports up to something
like nine videocards on the same PCI bus.  I do think there were
some limitations though (like they all had to be the same
videocard).  You might check out what they say about their
multi-head server on their web site (it's not their regular
server).

   XFree doesn't support multiple graphics adapters (not yet
anyhow).

                        MArk.

After bridging this across to the X news group, just incase we might
be able to generate some more information... please forgive me for
cross-posting this so much..

Recap: I was wondering if it was possible to use two video card/monitor
combination pairs under x-windows where each display would be separate
(ie: not a copy) system capable of displaying separate information
yet allowing the user/developer/programmer to access each with relative
ease. Maybe even move information between the two..

: The PCI bus allows more than one video card to coexist without conflicts,
: but I am not aware of any drivers for linux/X that support this. Under
: MSWindows you can only have one video driver, and it comes from the video
: card's manufacturer, and they're not going to support their competitors'
: cards :-) so in that case the cards would have to be identical (the Matrox
: Millenium is often mentioned for doing this under Windows). This
: limitation wouldn't apply to linux, but if you have to modify the drivers
: yourself it would probably make things easier. You might also have to
: modify the X server.

So then, and please argue with me here, if two or more PCI video cards
can co-exist without conflict (though there may be conflict in the
linear frame buffering) then wouldn't it be possible to run two
X Servers, one for each viedo card/monitor pair assuming that there was
a way to tell each X Server which card it was to have access to?

The problem arises in switching between the two servers...

: There is a program called x2x that allows the keyboard and mouse from one
: X display to control another X display (eg, the console plus an X
: terninal).  See ftp://gatekeeper.dec.com/pub/DEC/SRC/x2x/x2x-1.24.tar.gz
: This sounds like the easiest solution to me.

I'll have to check this out and see if this may handle the job. At work we
are able to actually drag windows across from one monitor to another
and the mouse pops out of the left side of one, and into the right side
of the other. I find this to be an amazing development tool allowing you
to view two screenfuls at one sitting with out paging between the two.

: You can use an old Hercules mono card but there are a couple of problems
: with this approach. First, all the ones I've seen are 8 bit cards, and if
: I understand this correctly, the VGA card also has to be used in 8 bit
: mode, which tends to slow things down. Many of the clone mono cards also
: emulate CGA (as grayscale) and this would conflict with the VGA card. I'm
: not sure what happens if the VGA card is on the PCI bus.

I think this Herc solution seems to be only 1/2 as good ( if not 1/4 or less)
as having two full fleged, full resolution, X 'windows' running.

So, it seems that there is some agreement that a PCI bus x86 may ba able
to handle two video cards. Now the question remains if the simple solution
of running two X servers, one for each card/monitor pair, would be
successful. If that is the case, then it just remains to get the two
servers to cooperate with each other in a reasonable way... right...

Any additional comments?

Dave

And not every SVGA chipset got the implementation right.

Right not the only one I've heard of that works is the matrox where you
can set a jumper to disable the VGA circuitary on the secondary cards.

Stephen

Let us know how you do.
K

--
------------------------------------------------------------------------

Silicon Graphics                        
1 Cabot Road                        work: (508) 562 - 4800

] There is a program called x2x that allows the keyboard and mouse from one
] X display to control another X display (eg, the console plus an X
] terninal).  See ftp://gatekeeper.dec.com/pub/DEC/SRC/x2x/x2x-1.24.tar.gz
] This sounds like the easiest solution to me.

This seems like it would be far more satisfactory than trying to get
multiple PCI cards to work.  Just get a second PC and put its monitor
on your desk.  From the man page it looks like it does the ``sliding
the mouse off one screen onto another'' trick, but I doubt it does
sliding windows from one screen to another.  The only system I've seen
do that is NeXTStep.
--
David Fox            http://www.cat.nyu.edu/fox            xoF divaD

: You can get special video cards with more than one VGA chipset on them.
: They come with drivers for Windows, but I've never heard of any drivers
: for linux/X. Brands that have been mentioned in the past include STB,
: Colorgraphics, Appian Graphics, and Tridium Research. It would be
: interesting to know if any of these manufactureres would be willing to
: release enough information to allow someone else to write a driver.

Does anybody know if there are any drivers dfor these cards?

Otherwise it seems that the best option in the Matrox cards and the Metro-X
server.

Dave

: >   Sure it does.  The PCI bus supports multiple video cards.
: >
: In theory.  And only one of them will be "normal" as in the above
: message.  ie. You can access it like a VGA.  All others has to be accessed
: by some other means.

I would suggest any linear frame buffer video card is no longer "normal" in
the sense that you can access it like a VGA.  Perhaps you mean beyond
this, but in what fashion would that be?

--
William Burrow  --  Fredericton Area Network, New Brunswick, Canada
Copyright 1997 William Burrow  
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And the one below it.

-- Pat

--
      This message does not represent the policies or positions
              of the Mayo Foundation or its subsidaries.

  Mayo Foundation                       phone:  507/284-9485

: So then, and please argue with me here, if two or more PCI video cards
: can co-exist without conflict (though there may be conflict in the
: linear frame buffering) then wouldn't it be possible to run two
: X Servers, one for each viedo card/monitor pair assuming that there was
: a way to tell each X Server which card it was to have access to?

Who will own the mouse? the keyboard?  There are very significant hardware
limitations and sharing problems with this idea.  Certainly, the two servers
would have to be aware of each other and share these resources like tokens
on a token ring.  Also, how would you address the screens?  Currently,
hostname:0.0 means something and hostname:1.1 refers to the same server but
a particular window (?).  You would have to revise this standard, wouldn't
you?

: So, it seems that there is some agreement that a PCI bus x86 may ba able
: to handle two video cards. Now the question remains if the simple solution
: of running two X servers, one for each card/monitor pair, would be
: successful. If that is the case, then it just remains to get the two
: servers to cooperate with each other in a reasonable way... right...

Right.  Legacy dictates a particular interfacing: are you willing to buck
against that?  Lastly, who would want to have two X11 servers on the same
machine?  Think about how much space that would require (even with the
shared libs)!  X11 supports client-based threading.  Is everyone sure that
the libs can handle threaded accesses from the _server_?

-Sean Walton, KB7rfa