Quadview possibe? (Quadro NVS 420)

[Xevious]

I was wondering if its possible to get a 'quad view' type of setup on linux with a Quadro NVS 420. Basically I wanna hook this sucker up to one monitor and hopefully be able to run 4x1920x1200 and have no xinerama info and thus the O.S. just sees one 3840x2400 desktop.

I know you can do this with 2x1920x2400 in a two port card but can you do this with this quad port card or is it just treated like two graphics card and thus you won't be able to have 3d over all 4 inputs or even have all 4 inputs treated like a single display?

[JaXXoN]

Hi!

The NVS420 integrates two GPUs behind a PCIe-Bridge and thus will
behave pretty much like two separate cards. Means: you can have
3D support up to the full resolution of 3840x2400 by enabling
Xinerama and there do exist a number of solutions to get the desired.
XineramaInfo. However, both, Xinerama and "Fakearama", come with
a number of problem. For details, please check the following threads:

http://www.nvnews.net/vbulletin/showthread.php?t=85604
http://www.nvnews.net/vbulletin/showthread.php?t=133740 (posting #2)

My recommendation is to purchase a single GPU card with two outputs,
then purchasing two Matrox TripleHead2Go boxes which are capable
of splitting a 3840x1200 signal from a single output into 2x 1920x1200. So
with twinview, you can hook up to four displays onto a single GPU in a
3840x2400 (2x 2x 1920x1200) or a 7680x1200 (4x 1920x1200) single
framebuffer configuration. The desired XineramaInfo behaviour
can easily be archived with nvidias "XineramaInfoOverride" option.

For details, please check
http://www.nvnews.net/vbulletin/showthread.php?t=126134
http://www.nvnews.net/vbulletin/showthread.php?t=106517

BTW.: in your case, a pair of Matrox DualHead2Go boxes
(which are cheaper than the TH2Gs) should basically also
do the trick for you, but I don't know if the modelines from the
posts, linked above, will work for them.

regards

Bernhard

[Xevious]

Unfortunately I really don't wanna spend $600 on matrox trippehead2go boxes to get what I want. If I could do it for around $300 on matrox converter boxes I would probably do it but $600 is just a bit too much for me when the monitor only cost me $800.

[JaXXoN]

Originally Posted by Xevious

$600 is just a bit too much for me when the monitor only cost me $800.

In case your requirements don't reach the limits of a multi-GPU Xinerama solution,
then you certainly don't need the Matrox boxes! However, I fear you need to undergo
the constant pain of such a solution until you are more than willing to spend the
$600 on those TH2G boxes :-)

regards

Bernhard

[Xevious]

Originally Posted by JaXXoN

In case your requirements don't reach the limits of a multi-GPU Xinerama solution,
then you certainly don't need the Matrox boxes! However, I fear you need to undergo
the constant pain of such a solution until you are more than willing to spend the
$600 on those TH2G boxes :-)

regards

Bernhard

And I ended up buying two th2g boxes and they won't even detect my monitor and I get no output... freaking sucks.

[JaXXoN]

Originally Posted by Xevious

And I ended up buying two th2g boxes and they won't even detect my monitor and I get no output...

The TH2G will only work for the 3840x1024 (3x 1280x1024) mode
OOTB!

For all other modes, you need a hand crafted xorg.conf (for
certain modes you can alternatively re-program the EDID field
of the TH2G to operate in a different mode by default, i.e. in
your case you could re-program the TH2Gs to operate as
2x 1920x1200 so that Xorg should just detected a pair of
TH2Gs in twinview mode without modification).

I suggest to try creating an xorg.conf specific to your setup.

Maybe the attached one is doing it for you (but I guess you
need to do some minor fine tuning).

For more details on how to operate TH2Gs with Linux, please
check the following postings:

http://www.nvnews.net/vbulletin/showthread.php?t=106517
http://www.nvnews.net/vbulletin/showthread.php?t=126134
http://www.nvnews.net/vbulletin/showthread.php?t=133740

If you still have troubles getting it working, then please don't
hesitate to come back here, again.

regards

Bernhard

[JaXXoN]

Originally Posted by JaXXoN

Maybe the attached one is doing it for you (but I guess you
need to do some minor fine tuning).

Oops, I have forgotten to add the modeline to the monitor section:

ModeLine "3840x1200" 308.00 3840 3904 3968 4160 1200 1203 1213 1235 +HSync +VSync

I have attached the updated xorg.conf

regards

Bernhard

[JaXXoN]

Originally Posted by JaXXoN

I have attached the updated xorg.conf

This is obviously not my day: I selected the file but forgotten to
click "upload", so here we go again ...

Bernhard

[Xevious]

Thats not the problem. I have used my windows laptop to setup the matrox tripple head 2 go and my monitor can pretty much take any resolution/input you set on it.

Using the GSM utility thing on my laptop it pretty much either doesn't or sometimes detects (and drops off) when setting up my display. This thing is acting like nvidia 7900 series cards that need the DVI detectives which means another $200 which I don't think I am willing to spend.

Too bad the triplehead2go seems incapable of forcing an output to a monitor (even if its not able to read DDC info).

[JaXXoN]

Originally Posted by Xevious

Using the GSM utility thing on my laptop it pretty much either doesn't or sometimes detects (and drops off) when setting up my display.

In deed, the GSM utility is PITA - this is why I recommended to create an
xorg.conf specific to your setup.

Originally Posted by Xevious

This thing is acting like nvidia 7900 series cards that need the DVI detectives which means
another $200 which I don't think I am willing to spend. Too bad the triplehead2go seems
incapable of forcing an output to a monitor (even if its not able to read DDC info).

I got the impression that the TH2G doesn't take the EDID of the attached displays
into account - you just supply a fixed modeline to the TH2G and it will just produce
the corresponding timing on the outputs.

Did you tried the xorg.conf I sent? If it doesn't work, then maybe you start off
with only TH2G on one DVI output with 3840x1200 mode and once that works,
you can add the second TH2G.

BTW.: what is the brand of your LCDs? You may like to ask Matrox support
if there are any know incompatibilities with this type.

regards

Bernhard

[Xevious]

Originally Posted by JaXXoN

In deed, the GSM utility is PITA - this is why I recommended to create an
xorg.conf specific to your setup.



I got the impression that the TH2G doesn't take the EDID of the attached displays
into account - you just supply a fixed modeline to the TH2G and it will just produce
the corresponding timing on the outputs.

Did you tried the xorg.conf I sent? If it doesn't work, then maybe you start off
with only TH2G on one DVI output with 3840x1200 mode and once that works,
you can add the second TH2G.

BTW.: what is the brand of your LCDs? You may like to ask Matrox support
if there are any know incompatibilities with this type.

regards

Bernhard

Trust me it does take into account. Before you even posted on this page I tried forcing the resolution with all the settings to not use EDID (I already had these from before the matrox triplehead2go):

(II) NVIDIA(0): --- Modes in ModePool for DFP-0 ---
(II) NVIDIA(0): "nvidia-auto-select" : 1024 x 768 @ 85.0 Hz (from: X Server, VESA)
(II) NVIDIA(0): "3840x1200" : 3840 x 1200 @ 60.0 Hz (from: X Configuration file ModeLine)
(II) NVIDIA(0): "3840x1200_60" : 3840 x 1200 @ 60.0 Hz (from: X Configuration file ModeLine)
(II) NVIDIA(0): "2048x1536" : 2048 x 1536 @ 60.0 Hz (from: X Server)
(II) NVIDIA(0): "2048x1536_60" : 2048 x 1536 @ 60.0 Hz (from: X Server)
(II) NVIDIA(0): "1920x1440" : 1920 x 1440 @ 75.0 Hz (from: X Server, VESA)
(II) NVIDIA(0): "1920x1440_75" : 1920 x 1440 @ 75.0 Hz (from: X Server, VESA)

If I unhook one of the ports and plug it into my cheap ass dell LCD I get 1920x1200 output as I expect.

The problem is that as I said the matrox card can't read the DDC information and thus refuses to output to the monitor. I am not running monitor(s) i am running a single monitor that takes 4 single link DVI connections.

I have seen certain vid cards have the same problem as the matrox triplehead2go (wont get any picture) but those were pretty much only the 7x00 series and earlier 8x00 series nvidia cards. Oddly enough someone on the T221 mailing list mentioned that they were able to drive the monitor with two matrox triplehead2go's which makes me wonder if an earlier revision of the hardware didn't have this problem (this is a hardware problem).

[JaXXoN]

Originally Posted by Xevious

Oddly enough someone on the T221 mailing list mentioned that they were able to drive the monitor with two matrox triplehead2go's

I guess the problem is that the T221 has a maximum refresh rate of 41 Hz
whereas the modeline (and the built-in EDID) assume 60Hz. Maybe it helps
to reduce the pixel clock frequency in the modeline 308.00 MHz to
308*41/60 = 210.46 MHz?

regards

Bernhard