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A few days ago I was lucky enough to obtain a free monitor and I decided to buy a VGA splitter to use it with my other screen. The splitter is an Aten VS92A, if it can be useful.

The device works perfectly, the signal goes to both screens, but for some reason the computer can't see it's connected to two different screens. Instead I see the same view on both monitors.

To clarify a bit the situation: I'm using a laptop, so in fact I now have three different screens (but the idea is to shut down the laptop screen as soon as everything works because it renders colors really badly) and the laptop screen is successfully distinguished from the other two. This also means that installing a new graphic card is sadly not an option. Other cables (e.g. HDMI) are also not an option.

I found other cases similar to mine, but I can't find a solution that works for me. As I understand, it seems that the computer doesn't identify the EDID of the second screen and to further confirm this hypothesis I can say that, if I switch the cables connected to the splitter, the resolution adapts to the best settings for the screen connected on port 1.

I also saw a lot of people saying: "with linux I see twice the same image and with windows a split screen." This means that the splitter sends all the useful information to the computer, but the computer can't see it or it doesn't even look for it. Sadly (not really) I don't have windows installed on my computer, so I can't verify this step, but the splitter manual said indeed that it is possible to obtain a split screen, otherwise I wouldn't have bought it.

Now, for the useful information about my computer:

uname -a
Linux #### 3.19.0-65-generic #73-Ubuntu SMP Tue Jun 28 17:02:53 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Desktop environment: MATE

cat /etc/X11/default-diplay-manager
usr/sbin/lightdm

xrandr -q
Screen 0: minimum 8 x 8, current 3286 x 1080, maximum 32767 x 32767
LVDS1 connected 1366x768+0+312 (normal left inverted right x axis y axis) 309mm x 174mm
   1366x768       60.0*+
   1360x768       59.8     60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
VGA1 connected 1920x1080+1366+0 (normal left inverted right x axis y axis) 473mm x 300mm
   1920x1080      60.0*+
   1680x1050      60.0  
   1280x1024      75.0     60.0  
   1280x800       59.8  
   1152x864       75.0  
   1280x720       60.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   848x480        60.0  
   640x480        75.0     72.8     66.7     60.0     59.9  
   720x400        70.1  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

And switching monitors on the splitter the same command shows (only the different part):

VGA1 connected 1440x900+1366+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900       59.9*+   75.0  
   1680x1050      60.0  
   1280x1024      75.0     60.0  
   1280x800       59.8  
   1152x864       75.0  
   1280x720       60.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   848x480        60.0  
   640x480        75.0     72.8     66.7     60.0     59.9  
   720x400        70.1 

Content of /var/log/Xorg.0.log: http://pastebin.com/TgfnQzJU

I can't find xorg.conf, but there are two files that have both the same content, formatted as a few examples of xorg.conf I found elsewhere, they are called xorg.conf.07292015 and xorg.conf.07302015 and their content can be found here: http://pastebin.com/gUBBGRti

The available drivers and the one in use can be found in this screenshot:

enter image description here

nvidia-settings -q all

returns an empty line.

Intuitively it seems to me that xrandr should see a VGA2 together with VGA1, but with different settings. Any suggestion?

10

+1 for all the research effort, however...

Hate to break it to you, but the fact is it's working as intended.

A splitter is just that - a splitter. Nothing more, nothing less.

All it will do for you is duplicate the signal.

A quote from the link you provided:

The VS92A is a video splitter that not only duplicates the video signal from any VGA, XGA, SVGA, UXGA, or multisync monitor to two outputs, but also boosts the video signal over a distance of up to 30 meters

  • So the splitter was a waste of money in the end. Well, thanks for the answer, even if it was not what I was hoping for. – GRB Jul 1 '16 at 13:09
  • @GRB - I must say though, the amount of research effort you did was impressive. You should consider contributing some answers here :) – Android Dev Jul 1 '16 at 13:13
  • I didn't list all these information because I'm an expert, but because before asking I looked at other similar questions which information were useful. I will consider contributing though, thanks. – GRB Jul 1 '16 at 13:26
  • @GRB - I am curious about something though. You said, "but the splitter manual said indeed that it is possible to obtain a split screen, otherwise I wouldn't have bought it". Could you elaborate? – Android Dev Jul 1 '16 at 13:28
  • I read the instructions again, I misunderstood the same sentence you quoted above. I read the part "or multisync monitor to two outputs" as "or sync to monitors". – GRB Jul 1 '16 at 16:04

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