From: Bennion, Brian (
Date: Tue Apr 11 2017 - 09:56:53 CDT


This "problem" is rampant among all the latest xorg products. The "baked in" security assumes that people don't use ssh to tunnel the x11 sessions.

Some linux distros allow one to added the iglx_enable at start up, others don't (ie FC 23).

It has been a pain in my screen for over a year now.


From: <> on behalf of John Stone <>
Sent: Tuesday, April 11, 2017 1:00:45 AM
To: Thomas Griffiths
Cc: Ryan P. Steele;
Subject: Re: vmd-l: VMD and latest XQuartz update

  Thanks for the solution. Yes, if indirect rendering is disabled
in XQuartz, that would completely explain the problem. I assume that
Apple closed off indirect rendering as some sort of approach to
improving the "default security" of the system.

  John Stone

On Tue, Apr 11, 2017 at 05:07:46PM +1000, Thomas Griffiths wrote:
> Hi John, Ryan;
> I may have a solution to this Xquartz and VMD issue. It is indeed an issue
> with XQuartz. I believe it has something to do with allowing XQuartz to
> allow indirect GLX contexts. (What that specifically means I don't know. My
> expertise here is lacking, but that's what I found being discussed online.)
> The following fixes my implementation.
> The fix is this: Quit XQuartz, then in the macOS Terminal application (on
> your own machine, *not* logged into the reomte cluster) run:
> defaults write org.macosforge.xquartz.X11 enable_iglx -bool true
> Reload your terminal and you should then be able to log into a remote
> machine and launch remote XQuartz sessions for VMD
> ---
> More indepth:
> Apparently, version 2.7.8 was the last release of XQuartz where indirect
> glx rendering was enabled by default. Which is why rolling back to this
> version works. There are a couple of posts out there (
> INdirect_glx_on_your_X_server) regarding enabling this indirect rendering--_000_CY1PR09MB082685DC3AB99800E3132887F6000CY1PR09MB0826namp_--