MATLAB HiDPI setting ignored on Linux (Ubuntu)

Hi,

I am running a fresh install of MATLAB R2022b on Ubuntu 22.04.

• Laptop: HP Zbook Fury G7 (screen resolution 3840x2160)
• GPU1: Intel Cometlake-H GT2
• GPU2: NVidia Quadro T1000.

MATLAB install script was executed as sudo, as described here (link [MATLAB]). There have been several related questions in MATLAB Answers (link1, link2, and many more related to Windows) but none seem to work for this case.

Few observations:

• If xrandr is not used, the scaling setting is completely ignored.
• Executing the xrandr with the calculated DPI, seems to affect only the splash screen, but not the MATLAB interface.
• After xrandr, changing the scaling setting in MATLAB affects the editor only (without restart). This is behavior is again lost after restart.
• Changing permission (as suggested by one comment) in the ~/.matlab file, did not work.
• Installing MATLAB as non-sudo yields the same results.

Anyone knows if there is anything else I could try? Besides lowering the screen resolution, since that results in blurriness.

Thanks!

Edit 1: Typo

Edit 2: Looking around it seems to be a permission issue. For testing purposes only, I added 'root' user to the license and when changing the scaling setting it is honored as expected. In the ~/.matlab folder for the root user, the main differences is the presense of *.mlsettings binary files. Although, giving full persmissions to the $USER for both ~/.matlab as well as /usr/local/MATLAB folder does not seem to affect the process in any way.

Current workaround: copying matlab.mlsettings file from the root to the user's .matlab directory seems fix the issue. But this is far from a solution. Modyfing any setting of these settings/preferences require to first run matlab as root, make the modifitiations and then copy-paste the relevant *.mlsettings files. Will update when I have more.

Edit 3: A better workaround (no root needed): It seems that if a desktop launcher is used (matlab-support package), bash is not run in advance and MATLAB does not access the system enviroment variables, including the TMPDIR/TMP. Then (for some reason..) MATLAB can not access the /tmp/ folder and this is probably where things break. Two ways go around this are:

1. Run matlab from terminal where bashrc is already sourced (including for example a TMP var to an accessible folder, e.g. ~/.tmp/).
2. Or, change the default MATLAB tempdir. This is inspired from the workaround of 'Invalid cross-device link (18)' error I also exprerienced when trying to save a document (link3). Although, this setting is again lost after a restart, at least for me.