Endless log spam _CGXGLDisplayContextForDisplayDevice: No matching context for device

[Carlo]

Thank you BMT and others,

Will take your advice, hopefully won't find issues with this change.

Cheers,
Carlo

[jb8748]

My view is that the DisplayLink installation should not edit the global asl.conf file in any way. I don't think it's the right approach for installers to alter system files when there are other alternatives.

You should use an ASL module, like I outlined in my blog post. My reasoning is:
1) asl.conf can be overwritten at anytime by a system update
2) it is clear who has requested that these stop entering the log - and this itself is logged when ASL starts
3) ASL will/should deal gracefully with cases where people have multiple 'claims' on the messages
4) Removing this (such as when uninstalling the drivers completely) becomes trivial as it's one file to delete. Removing an edit to asl.conf, which may have been subsequently edited, isn't going to be reliable.

Just my thoughts. Looking forward to this making it into the standard installation.

James

[BMT]

Originally Posted by jb8748

My view is that the DisplayLink installation should not edit the global asl.conf file in any way. I don't think it's the right approach for installers to alter system files when there are other alternatives.

While I would normally agree that it's bad to alter system files, the method you outlined in your blog post has never worked for me - editing asl.conf is the only method that has.

[luckman212]

I thought that it was "fixed" but I noticed today these logspam messages continue to appear for me even as of v2.4 (Jul 3 2015) so I had to re-enable this patch.

[dude123]

Sadly this has become a topic again under 10.12 Sierra. My syslogs get hit by 60.000 messages per second. And none of the above hints helps, also the asl-config coming with the displaylink 3.0 driver doesn't help. Anyone an idea about this?

[Carlo]

Originally Posted by dude123

Sadly this has become a topic again under 10.12 Sierra. My syslogs get hit by 60.000 messages per second. And none of the above hints helps, also the asl-config coming with the displaylink 3.0 driver doesn't help. Anyone an idea about this?

Can you please copy and paste the log message? It may be a new one.

Kind regards,
Carlo

[dude123]

Originally Posted by Carlo

Can you please copy and paste the log message? It may be a new one.

Yes sure!

 No matching context for device (0x7fe957c26f90) - disabling OpenGL

Sender:
/System/Library/PrivateFrameworks/SkyLight.framework/Resources/WindowServer
(/System/Library/PrivateFrameworks/SkyLight.framework/Versions/A/SkyLight)

Subsystem:
com.apple.SkyLight

[silence]

Originally Posted by Carlo

Can you please copy and paste the log message? It may be a new one.

Kind regards,
Carlo

Can confirm this is an issue on Sierra 12.12.5. My log looks exactly like dude123's, and the existing fix no longer works.

[skew4]

Originally Posted by dude123

My syslogs get hit by 60.000 messages per second.

Indeed:

# log show --last 6h --predicate 'messageType == error and processImagePath endswith "DisplayLinkManager"'

Timestamp                       Thread     Type        Activity             PID    
2018-02-08 09:34:12.277266  0xf609a    Error       0x0                  115    DisplayLinkManager: (CoreFoundation) Detected potentially harmful notification post rate of 60.0026 notifications per second

This message shows up even with the "level: off" workaround (but infrequently).

The fact that my monitors run at 60Hz is likely not a coincidence.