A problem in remote connection to montague

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Please describe the issue you’re having?

I am writing about a problem in remote access to montague. I ssh to bic network using putty and use X2Go for remote connection. But recently there seems to be a problem in access to graphic card in my remote connection.
The main problem occurs when I try to plot something in matlab. The fonts on the figure are so huge that I cannot see the labels. Furthermore, I’ve got this error in matlab:

MATLAB has experienced a low-level graphics error, and may not have drawn correctly.
Read about what you can do to prevent this issue at Resolving Low-Level Graphics Issues then restart MATLAB.
To share details of this issue with MathWorks technical support,
please include this file with your service request.

I’d be grateful if you could help me solving this issue,

  • Soheila Samiee

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What is the expected behavior VS. what is happening?

Steps to reproduce the problem?

Has this happened before, or is it the first time?

Please review the following link and provide us with the output
of the command ‘opengl info’ from the matlab command prompt.


Thank you for the suggestion,
I have already reviewed the link, and tried to solve the issue but no success!
I cannot change the graphic to opengl in matlab, I get this error:
“Switching to hardware OpenGL rendering at runtime on unix is not supported.”

I also tried starting matlab in opengl format (matlab15b softwareopengl), but it did not fix the problem with plots.

This is the opengl info from matlab command prompt:

                      Version: '2.1 Mesa 7.2'
                       Vendor: 'Brian Paul'
                     Renderer: 'Mesa X11'
               MaxTextureSize: 2048
                       Visual: 'Visual 0x6e, (RGBA 32 bits (8 8 8 8), Z depth 1?'
                     Software: 'true'
         HardwareSupportLevel: 'none'
    SupportsGraphicsSmoothing: 0
SupportsDepthPeelTransparency: 1
   SupportsAlignVertexCenters: 0
                   Extensions: {114x1 cell}
           MaxFrameBufferSize: 4096
1 Like

That’s normal: the hardware rendering is not available when running matlab remotely.

You will have to check your X2Go client, did you upgrade it recently?
What OS is your client? A Mac?
What is the session manager and resolution that you use on the client?

I upgraded it a few months ago (late 2016).
My client is windows 10, and I use mate with DPI equal to 250.

You didn’t mention if the problem occurred before or after the client upgrade.

Have you tried with other session managers – other than mate?
Have you tried different resolutions on your client?
Do you have any sort of compression settings on your client?
Have you tried the same thing on a different host than montague?


there was a recent release of the x2go client for WIndows, I suggest you try it!


Thank you for your suggestions,
I upgraded the X2Go client to the most recent version (the one that Sylvain mentioned), but the problem is still there.

And in reply to Francois’s suggestions,

  • I already tried other session manager than mates, they are even worse because a part of screen is missing and I can not see the bottom part of the page!
  • Yes, I did try different DPIs but did not help for the figures. I should re-enphesize that anything other than matlab figures looks OK in the remote desktop.
  • No, I do not have compression set up on the client.
  • I tried rosaline, it is not perfect, but much much better than montague (font size in matlab figures are big, but not huge)!

Should be something wrong in server side, and probably particularly for matlab!

All the Best,

compression is on by default but in the connection tab (session management mode), set the compression method to 4k-png - this should give you good results.

montague is running ubuntu precise, for which support ends this coming April while rosaline is running ubuntu trusty;
since montague is scheduled to be upgraded to trusty, I would suggest we do this first.

if you log out of montague, I can do this today but we should first make a backup of /export01/data and disconnect your USB drives. Do you have a backup of /export01/data ?

OK, I did not know that, I changed it to 4k-png.

Actually, in general, the fonts are smaller and look more natural on montague compared to rosaline (for example the name of the folders, and the items in the menus), I think the main problem should be somewhere in matlab!
Anyways, if this upgrade should be done soon, I agree, it would be better to do it as the first step. But unfortunately I have some files open on my workstation, and I am not in the lab today to save and close everything before logging out. If it is not very time consuming we can do it one day next week after 5 pm.
By the way, I do not have anything in /export01 all my files are on /export02, and they are backed up.

Thank you,

you have your VM in /export01/data/Win/ … close it (if opened) before making a backup!

whenever you’re ready, just tell me and I can initiate the upgrade.

I see that your x2goagent on montague is running at DPI=500. I doubt that your screen has such resolution and I would recommend running it at the default value of 96. You can confirm your screen resolution with the following command:

xdpyinfo | grep dots

this may indeed affect the selection of fonts.

Ok, I will try lower DPIs, but as far as I remember I tried a few options (starting from 100), and 500 was a good candidate considering the screen fonts in general. Actually, even if screen resolution is low, going above 100 made the fonts smaller, which resulted in more natural screen to my eyes!
I can bring my laptop to the lab later this week to show you how the screen and figures look like with different options and on different workstations. And certainly it would be much faster and easier to try out your suggestions.

Thank you,

I installed virtualgl on workstations running Ubuntu trusty (https://virtualgl.org/About/Introduction)

hence, to run any application which requires and/or benefits from hardware OpenGL acceleration, use the following:

$ vglrun $My_OpenGL_App

Some examples …

$ vglrun brainstorm
$ vglrun register
$ vglrun Display