MantisBT - ardour
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0007668ardourbugspublic2018-09-29 10:012018-10-12 10:07
5.X git (version in description) 
0007668: VST plugins crashing due to 'idle' implementation
Back on 30th July, commit #98769796d7 modified 'libs/ardour/' to remove an 'idle()' implementation when responding to the VST message 'audioMasterUpdateDisplay'. This was done in response to a bug reported on the Mixbus forum which was causing a particular plugin to crash:- [^]

I've just noticed that commit #9ccace8f0d effectively re-implemented the idle functionality (albeit using a different strategy). However, this has simply re-introduce the bug - which now affects other plugins apart from the original one:- [^]
See Tassy's Youtube video here:- [^]
Reverting commit #9ccace8f0d removes the crashes
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Issue History
2018-09-29 10:01johne53New Issue
2018-09-30 12:34x42Note Added: 0020393
2018-10-01 04:00johne53Note Added: 0020394
2018-10-04 02:12user3465Note Added: 0020395
2018-10-04 02:13user3465Note Edited: 0020395bug_revision_view_page.php?rev_id=611
2018-10-04 06:58x42Note Deleted: 0020395
2018-10-12 10:05johne53Note Added: 0020398
2018-10-12 10:06johne53Note Edited: 0020398bug_revision_view_page.php?bugnote_id=20398#r613
2018-10-12 10:06johne53Statusnew => resolved
2018-10-12 10:06johne53Resolutionopen => fixed
2018-10-12 10:06johne53Assigned To => johne53
2018-10-12 10:07johne53Note Edited: 0020398bug_revision_view_page.php?bugnote_id=20398#r614

2018-09-30 12:34   
If you revert 9ccace8f0d then you can also remove the function fst_audio_master_idle() form the codebase.

But I think the issue is rather in

void fst_audio_master_idle(void) {
  while(g_main_context_iteration(NULL, FALSE));

that may live-loops if a system is overloaded and never idles. Or there may be a deeper event-loop issue here.

PS. 98769796d7c is unrelated here, that called the plugin's effEditIdle.
2018-10-01 04:00   
Thanks Robin,

It looks like fst_audio_master_idle() got added a few years ago to solve a different issue with VST plugins but I've a feeling it shouldn't get used as a response to this particular event. In this case I'd be tempted to take it out as it mostly seems to cause problems.
2018-10-12 10:05   
(edited on: 2018-10-12 10:07)
This seems fixed now if somebody wants to mark it as resolved

[Edit...] oops - I just realised I can do it myself !!