Quadview possibe? (Quadro NVS 420)

[JaXXoN]

Originally Posted by JaXXoN

T221 has a maximum refresh rate of 41 Hz

Just recognized that there are different models - there's also one with 48 Hz.
So 246 MHz might do it.

BTW.: just recognized from the modeline that the horizontal total is 4160
pixel, which exceeds the limit of the corresponding EDID field (4095), so
you for sure need to create an xorg.conf (changing the default EDID won't
help in your case despite told otherwise, before).

regards

Bernhard

[Xevious]

Originally Posted by JaXXoN

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

That doesn't matter as its not reading the EDID info and it will take a 60 Hz signal even though the internal refresh rate is 41 Hz.

[JaXXoN]

Originally Posted by Xevious

That doesn't matter as its not reading the EDID info.

I just did the following experiment:


1. Unplugged one LCD from the TH2G, resulting in no signals on the
TDMS lines.

2. Put a 2.2K resistor between Pin 14 (+5V) and Pin 16 (Hotplug
detect): every time I connect the resistor I can see that the
DDC clk and data lines are active (using an oscilloscope).
I assume the TH2G tries to acquire the EDID. (there are still
no signals on the TDMS lines).

3. Re-Plug the LCD - working


So I it looks like you are right and the TH2G won't generate signals
on the TDMS lines unless it gets a proper EDID through DDC.

You may ask Matrox support if they could supply a firmware that
addresses your problem.

regards

Bernhard


P.S.: if you know how to operate a soldering iron, you can "easily"
create those DVI detectives on your own: the EDID is transfered
through DDC following the I2C EEPROM protocol. An 1K I2C EEPROM
(24C01) as needed for the EDID costs around $1, but programming it
with some fake EDID and connecting it to the DDC lines (4 times)
probably takes you a day or so :-)

[Xevious]

Well I finally broke down and bought the DVI detective =( Once I did that I had no problems except the ordering of the inputs.

Aparrantly When running 3840x2400@33 Hz using two inputs the monitor had inputs like:

A1 A2

So i figured that going to four displays it would be:

A1 A2
B1 B2

(in reading order). Thus each matrox triplehead2go would drive each half of the screen (vertically). Well what ended up happening was:

A1 B1
A2 B2

This isn't very optimum as when I am running in single output mode (BIOS post and what not) I am only seeing half the screen. I might see if I can get the triplehead2go's to do 1920x2400 (twice) instead of 3840x1200 (twice) to solve this issue. I took some pictures of my setup here if anyone is curious:

http://box.houkouonchi.jp/vp2290b_60hz/

Someone said something about all 4 links needing to be genlocked or something but so far its worked everytime X has started up and there is only a very very slight amount of tearing. It might seem so slight because its @ 41Hz but it was barely noticeable even when running a game so I don't think they are gen locked but I am having no problems getting the full refresh rate.

This ended up being more expensive than I expected. I got $80 off the dvi-detectives as I bought open boxed ones off ebay which prompted me to do this whole thing (as it took off $160 from the original $600 price tag) but the 4 DVI detectives after tax/shipping were about $230 or so which means it ended up costng me a bit over $700 after everything was said and done =( Only $100 less than my vp2290b itself cost.

I have to admit that it feels soo much nicer at 41 Hz though. Before it felt like there was input lag when dragging my mouse and now games are actually playable at the full resolution. Running. I definitely noticed an immediate difference in just everyday use of the monitor.

[JaXXoN]

Originally Posted by Xevious

This isn't very optimum as when I am running in single output mode (BIOS post and what not) I am only seeing half the screen.

I had a similar problem: with the default EDID settings, the TH2G splits the BIOS/post
screen to the three attached LCDs, so that each LCDs shows 1/3 of the screen.
Means: the output was pretty distorted. The solution was to delete the wide screen
EDID and just keep the single LCD EDID flashed (i.e. 1680x1050 for me). This way
the signal is only generated on one output (which in your case should be 1920x1200
scaled up, I assume).

Originally Posted by Xevious

I took some pictures of my setup here if anyone is curious:
http://box.houkouonchi.jp/vp2290b_60hz/

Impressive! Glad you got it finally working.

Originally Posted by Xevious

I have to admit that it feels soo much nicer at 41 Hz though. Before it felt like there was input lag when dragging my mouse and now games are actually playable at the full resolution. Running. I definitely noticed an immediate difference in just everyday use of the monitor.

Plus you could now use eye-candy like compiz if you like :-)

regards

Bernhard

[Xevious]

Originally Posted by JaXXoN

I had a similar problem: with the default EDID settings, the TH2G splits the BIOS/post
screen to the three attached LCDs, so that each LCDs shows 1/3 of the screen.
Means: the output was pretty distorted. The solution was to delete the wide screen
EDID and just keep the single LCD EDID flashed (i.e. 1680x1050 for me). This way
the signal is only generated on one output (which in your case should be 1920x1200
scaled up, I assume).

Do you mean add a mode that is just a single monitor? I don't really get how deleting the wide screen edid mode is going to help me here as I am widescreen.

Originally Posted by JaXXoN

Plus you could now use eye-candy like compiz if you like :-)

regards

Bernhard

I already was (beryl/XGL) but what going this route did was give me a better refresh rate (Before I was just running it off two DVI inputs and thus only got a bit over 30 Hz before).

[JaXXoN]

Originally Posted by Xevious

Do you mean add a mode that is just a single monitor?

Exactly!

Originally Posted by Xevious

I don't really get how deleting the wide screen edid mode is going to help me here as I am widescreen.

If you delete the wide screen mode from the TH2G EDID list, then Xorg won't
auto-detect the TH2G any more for the 3840x1200 mode, but you can force the
X-Server to generate the necessary output by adding appropriate options to
xorg.conf (please check the xorg.conf attached to posting #8, above) and the
TH2G will go into the appropriate mode: the actual modes displayed are
independent from the EDIDs stored! In fact, certain wide screen modes can't
be stored in the EDID (i.e. 5040x1050), because the pixel timing values are
beyond the 12 bit limit (4095) of the EDID pixel timing fields, so in those cases,
hand-crafted xorg.conf files are the only way to go.

In this context, I'm wondering how the modeline for the 2x 1920x1200 mode
fits into the EDID since the horizontal total (4160) is beyond the 12 bit limit.
Maybe the TH2G is using a different timing setting in case it needs to store
it in the EDID. It would be interesting to see what timing values your X-server
detects - can you please generate an nvidia-bug-report.log and post it? TIA!
regards

Bernhard

[Xevious]

Originally Posted by JaXXoN

Exactly!
and the TH2G will go into the appropriate mode: the actual modes displayed are
independent from the EDIDs stored! In fact, certain wide screen modes can't
be stored in the EDID (i.e. 5040x1050), because the pixel timing values are
beyond the 12 bit limit (4095) of the EDID pixel timing fields, so in those cases,
hand-crafted xorg.conf files are the only way to go.

Ok, that makes sense! I didn't know this was the case. This makes me think I can setup some custom modelines for doing 2x 1920x2400 instead of 2x 3840x1200 which would work better for my setup as well.

Just knowing that this is the case is all I needed as by default I can only get 25 Hz at 3840x2400 so I was already doing some wacky stuff b4 to get 33 Hz by completely ignoring EDID, IE:

 Modeline "1920x2400" 164.999 1920 1936 1968 2032 2400 2401 2404 2409 -hsync +vsync

    Option "DPI" "75 x 75"
    Option "ExactModeTimingsDVI" "true"
    Option "UseEDID" "FALSE"
    Option "ModeValidation" "AllowNon60HzDFPModes, NoEdidModes, NoEdidDFPMaxSizeCheck, NoVertRefreshCheck, NoHorizSyncCheck, NoMaxSizeCheck, NoDFPNativeResolutionCheck"
    Option     "TwinView"
    Option     "NoTwinViewXineramaInfo" "1"
    Option     "MetaModes"  "1920x2400,1920x2400; 1920x1200,NULL; 1600x1200,NULL; 1600x1200, 1600x1200; 1280x1024, 1280x1024; 1280x1024 , NULL; 1024x768, 1024x768; 1024x768, NULL; 800x600,800x600; 800x600, NULL; 640x480, 640x480; 640x480, NULL"
    Option     "TwinViewOrientation"      "RightOf"
    Option      "ConnectedMonitor" "DFP-0, DFP-1"

Do you know how smart the triplehead2go is with modes? Will it pretty much take any mode I give it and just divide the horizontal resolution by 1, 2, or 3, depending on how many displays are hooked up or will it actually be smart to divide it vertically if say the height is higher than the width? IE whatever is higher (width or height) it divides the input either horizontally or vertically?

[JaXXoN]

Originally Posted by Xevious

Do you know how smart the triplehead2go is with modes? Will it pretty much take any mode I give it and just divide the horizontal resolution by 1, 2, or 3, depending on how many displays are hooked up or will it actually be smart to divide it vertically if say the height is higher than the width? IE whatever is higher (width or height) it divides the input either horizontally or vertically?

No, the TH2G is very picky concerning the horizontal timing values - as far as I
could figure it out, the box will only do the splitting when very specific horizontal
timing values are supplied. The box seems to be tolerant concerning the vertical
timings and the pixel clock - but so far, I only tried variants that are only off by a few
percent from the default settings. And to my knowledge, vertical splitting is not
possible at all!

It might be possible to generate at 3840x2400 signal on just one DVI output which
the TH2G might splitt into 2x 1920x2400, but this would be just around 25Hz.

However, I'm wondering if in your special case you could get away without *any*
of the TH2Gs by using a simple twinview setup (off on GPU): each of two DVI
outputs generate a 1920x2400 signal at 48 Hz and the two outputs are then
combined into a single screen with twinview.

I have attached an xorg.conf that might work for you.

regards

Bernhard

[JaXXoN]

Originally Posted by JaXXoN

However, I'm wondering if in your special case you could get away without *any*
of the TH2Gs by using a simple twinview setup (off on GPU): each of two DVI
outputs generate a 1920x2400 signal at 48 Hz and the two outputs are then
combined into a single screen with twinview.

I downloaded the user guide for the VP2290b and it seems that each of the four
channels is just a single link DVI with a maximum of 165MHz, so the proposed
"TH2G-less" variant would only work at 25 Hz.

The user guide mentions a dual link (d-l) 3840x2400 mode on channel 1, but that
wouldn't gain you anything either (again, 25 Hz).

BTW.: it seems like that the VP2290b is reporting an EDID, but only on channel 1.
This is why the TH2Gs get confused and you needed those DVI detectives.
(maybe you can take that one for channel 1 out, but that's not going to be a big
win, then).

You may like to experiment with a modeline that has a 40.9 Hz / 48 Hz
refresh frequency in order to come close to the internal standard / extended
refresh rates. Maybe that has an influence on the tearing that you have
recognized.

ModeLine "3840x1200_48.0" 246.60 3840 3904 3968 4160 1200 1203 1213 1235 +HSync +VSync
ModeLine "3840x1200_40.9" 212.13 3840 3904 3968 4160 1200 1203 1213 1235 +HSync +VSync

regards

Bernhard

[Xevious]

Originally Posted by JaXXoN

BTW.: it seems like that the VP2290b is reporting an EDID, but only on channel 1.
This is why the TH2Gs get confused and you needed those DVI detectives.
(maybe you can take that one for channel 1 out, but that's not going to be a big
win, then).

Actually the VP2290b reports EDID information on both ports (that is not correct) and that is not why I needed the DVI detectives. I purely needed the DVI detectives because of the voltage issue that some video cards also have which cause them not able to read EDID on the monitor (geforce 7x00 and earlier 8x00). Interesting enough the DVI detective seemed to not need dvi-detectives in the past when someone else tested it (maybe an earlier revision had slightly different hardware causing it to not need them.

Originally Posted by JaXXoN

You may like to experiment with a modeline that has a 40.9 Hz / 48 Hz
refresh frequency in order to come close to the internal standard / extended
refresh rates. Maybe that has an influence on the tearing that you have
recognized.

ModeLine "3840x1200_48.0" 246.60 3840 3904 3968 4160 1200 1203 1213 1235 +HSync +VSync
ModeLine "3840x1200_40.9" 212.13 3840 3904 3968 4160 1200 1203 1213 1235 +HSync +VSync

regards

Bernhard

Ah, thanks for that. I will give those a try. Running at the actual refresh rate could possibly help with the horizontal tear line I am seeing (its only slight).

[rubin427]

Originally Posted by JaXXoN

...The NVS420 integrates two GPUs behind a PCIe-Bridge and thus will
behave pretty much like two separate cards. ...

Thank you! Very useful info that I had overlooked.