Note that the above declaration is missing a space between Message and _CGX... should be

Hi Carlo, the string you proposed is formatted incorrectly, it would need to be as follows instead else it won't work:
? [= Sender WindowServer] [S= Message _CGXGLDisplayContextForDisplayDevice] ignore

I've confirmed the above works as intended.

PS. Make sure to put the string at the top of asl.conf else it won't work! (Due to other rules taking priority over it and cancelling out the effect). I'm not sure if S= or =S (as you proposed) makes any difference, but I've only ever seen it as S= which is why I put it that way round.

Also, if you're thinking of doing this automatically you should make sure to check there's not already a string containing _CGXGLDisplayContextForDisplayDevice OR WindowServer in asl.conf, as people may have already added the same or a different string to stop it from happening already.

Edit: Looks like someone else beat me to it, I've been trying to post this for the past few days but kept getting forum errors each time I did. The 4th page of the topic wasn't even showing up until I posted my message! Weird.

Thank you BMT and others,

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

Cheers,
Carlo

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

As I see it, this was all team work. I would have never come to this if it weren't for your blog post and postings from others. :-)

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.

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.

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

Yes sure!

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

Subsystem:
com.apple.SkyLight