Error using Screen

Hardware
1

Bug report is showed below:
PTB-INFO: This is Psychtoolbox-3 for GNU/Linux X11, under Matlab 64-Bit (Version 3.0.17 - Build date: May 14 2021).
PTB-INFO: OS support status: Linux 5.4.0-73-lowlatency Supported.
PTB-INFO: Type ‘PsychtoolboxVersion’ for more detailed version information.
PTB-INFO: Most parts of the Psychtoolbox distribution are licensed to you under terms of the MIT License, with
PTB-INFO: some restrictions. See file ‘License.txt’ in the Psychtoolbox root folder for the exact licensing conditions.

PTB-INFO: For information about paid priority support, community membership and commercial services, please type
PTB-INFO: ‘PsychPaidSupportAndServices’.

PTB-INFO: Many graphics cards do not support proper timing and timestamping of visual stimulus onset
PTB-INFO: when running in windowed mode (non-fullscreen). If PTB aborts with ‘Synchronization failure’
PTB-INFO: you can disable the sync test via call to Screen(‘Preference’, ‘SkipSyncTests’, 2); .
PTB-INFO: You won’t get proper stimulus onset timestamps though, so windowed mode may be of limited use.
PTB-WARNING: Your graphics driver doesn’t allow me to control syncing wrt. vertical retrace!
PTB-WARNING: Please update your display graphics driver as soon as possible to fix this.
PTB-WARNING: Until then, you can manually enable syncing to VBL somehow in a manner that is
PTB-WARNING: dependent on the type of gfx-card and driver. Google is your friend…

PTB-WARNING: Seems that a Mesa OpenGL software renderer is active! This will likely cause miserable
PTB-WARNING: performance, lack of functionality and severe timing and synchronization problems.
PTB-WARNING: Most likely you are running Psychtoolbox on a Matlab version 8.4 (R2014b) or later and
PTB-WARNING: Matlab is causing this problem by overriding your operating systems OpenGL library with
PTB-WARNING: its own outdated software library. Please run the setup script PsychLinuxConfiguration()
PTB-WARNING: now from your Matlab command window and then quit and restart Matlab to fix this problem.

PTB-WARNING: Actually, it is pointless to continue with the software renderer, as that will cause more trouble than good.
PTB-WARNING: I will abort now. Read the troubleshooting tips above to fix the problem. You can override this if you add the following
PTB-WARNING: command: Screen(‘Preference’, ‘ConserveVRAM’, 64); to get a functional, but close to useless window up and running.

>>What I did for trying to solve this problem:
Step 1: I repeated the suggestion showed in the bug report, by running PsychLinuxConfiguration. It appeared that I successfully installed those files recommended by Author step by step. However, I reboot and reopen matlab and run Screen(‘OpenWindow’,0,[128,128,128],[0,0,300,300]) command, and this bug report happened again.

Step 2: I surfed internet and searched the same question asked by JacopoTurini on Github. And I applied the method provided by Professor Kleinerm (See page: Problem with graphics driver and Mesa OpenGL · Issue #536 · Psychtoolbox-3/Psychtoolbox-3 · GitHub). After I ran command “sudo apt-get install matlab-support” and finished this installation, I reboot and restarted maltab, however, this bug was still there when ran Screen(‘OpenWindow’,0,[128,128,128],[0,0,300,300]). I already installed Nvidia drivers (460 proprietary)

I really want to know how to solve this problem, please help me! Very THX!!

The software and OS are: MATLAB(R2021a), Ubuntu 20.04 LTS.

The hardware: Mi-Gaming-Laptop, CPU: core i7-9750H, GPU: GeForce RTX 2060 mobile / Gaphic HD 630.

2

Did you agree to replace the libraries when asked by the installer? You can try to install this again by un/reinstalling:

sudo apt purge matlab-support
sudo apt install matlab-support

make sure you are installing to the correct MATLAB install and say YES to replace the C++ libraries.

Possible additional problems

  • Your laptop is a hybrid (i.e. it has 2 different GPUs), and this can cause problems; Mario has mentioned some workarounds before, though I don’t remember what OS they were aimed at but search these forums.
  • You are using the proprietary NVidia driver but are you sure that Nouveau (the open-source MESA driver) is properly inactivated? Did you try with the Nouveau driver rather than proprietary one to see if it works better (although performance is much worse apparently).
3

Thank you so much for your suggestions!

I accept your advises by testing step by step today:

Firstly, I inactivated Nouveau driver and checked it by command “lsmod | grep nouveau”, and no value displayed.
Then I purged matlab-support and reinstalled it. It seemed that PTB worked correctly when I ran command “Screen(‘OpenWindow’,0,[128 128 128],[840,440,1020,640]);”. However, when I quit Matlab and restarted Matlab, there was a warning message (showed below):

2021-05-25_17-53
2021-05-25_17-531187×853 8.77 KB

I searched some forums for correcting this warning message by running “opengl(‘save’,‘software’);” on Matlab. However, I can’t successfully run command “Screen(‘OpenWindow’,0,[128 128 128],[840,440,1020,640]);” on Matlab again. The bug report showed before was again displayed.

Sincerely I want your help again for fixing this problem. Very Thx.

4

You need to get hardware OpenGL running, you can’t use this command. Try uninstalling and reinstalling MATLAB, then installing matlab-support again. This is a MATLAB error, so you could get support from Mathworks, they perpetually have OpenGL hardware problems with every release.

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