Panagement/CliptIt crashing on Arch Linux

[p0nce]

Probably Panagement-related but:

Panagement + LV2 + Arch + Ardour5 => crash after a few seconds

Panagement + LV2 + XUbuntu 18.04 + Bitwig => crash after a few seconds

The plugin crashes all by itself after a few seconds. Repeatedly. Reload, wait perhaps 5 seconds doing absolutely nothing, then crashes.

[p0nce]

This is really looking like a bad fix inside Panagement, except one report even say:

on Arch too (Manjaro) when using Ardour5, Panagement LV2 loads with a fuzzy look (all scrambled and zagged) then violently crash (and crashes ardour).

which is something different...

[p0nce]

Lots of users are reporting normal function, except some on Arch mostly.

[p0nce]

https://forum.audacityteam.org/viewtopic.php?f=48&t=108249 Two reports of Audacity crash, this time with a trace.

[p0nce]

Bug with audacity reproduced:

 Most likely this is a multi-threaded client and XInitThreads has not been called

I just though XInitThreads was to be called by the host and not the plugin...

[p0nce]

I think our own mutex should go and we should use XLockDisplay / XUnlockDispla+ our own mutex ( in case XInitThreads wasn't called)
This way the plugin host still choose whether it uses XInitThreads or not.

[p0nce]

X11 Race regression fixed in v9.1.8. This fixed at least the Audacity crash. I suspect other crashes are due to the same race, but maybe with some Arch specifics, difficult to know without testing on Arch.

[p0nce]

Probably fixed since v9.1.8, should test when given the chance.

[psychedel]

How can I help with tests here? I use Arch

[p0nce]

Hello,

If you can build a LV2 plug-in using the latest Dplug ~master and it works in Ardour, I think will prove that Dplug plug-ins work on Arch.
You can follow the dplug tutorial here in the Wiki: https://github.com/AuburnSounds/Dplug/wiki/Getting-Started

[psychedel]

Ok, from what I've tried:
In Ardour / LV2:

• Destructatorizer works
• The plugin "CLIP It" could not be loaded
  See the Log window for more details (maybe)

In Reaper / VST3:

• "CLIP It" crashes Reaper (segmentation fault)
• Destructatorizer works

I will try more tomorrow.
P.S. Thanks for the such a wonderful project (just found it today) it's really perfect to avoid C++/Rust for VST development!

[p0nce]

Hello,

Would it work with ClipIt if you comment out the onDrawRaw method? This part is basically a recent test for Canvas-like functionnality that is very recent.

Thanks for the praise :) We're trying to stay practical

[psychedel]

Without onDrawRaw - ClipIt works as VST3 in Reaper, but screen issue in Ardour (LV2).

[p0nce]

Cool you found the same glitch as #467 !
Apart from the CliptIt crash (recent regression), #439 and #467 looks dupe.

[psychedel]

Ok, I'm still learning the internals of the Dplug.
But for now, I can help with testing on Linux/Windows with Reaper/Bitwig/Ardour
(hope to get some debugging environment in Linux soon, working from VS Code)

[p0nce]

Basically both bugs are the same it's a race condition in window/dplug/window/x11window.d, one of the "finer" part of the library.

[p0nce]

Found a bug with ClipIT + Ardour6 + LDC + LV2 + debug build on Manjaro + KDE

• instantiate twice
• open/close one interface , then the other, it cash in XCheckEventWindow for the non-closed window

[p0nce]

To fix it, XEvent from the dead window needs to be pulled from the queue manually before the other window can call XCheckEventWindow.

diff --git a/window/dplug/window/x11window.d b/window/dplug/window/x11window.d
index ba2dcf4c..493c8180 100644
--- a/window/dplug/window/x11window.d
+++ b/window/dplug/window/x11window.d
@@ -653,8 +653,19 @@ private:
         XFreeGC(_display, _graphicGC);
         freeBackbuffer();
         XDestroyWindow(_display, _windowID);
-        unlockX11();
 
+        // We need to flush all window events from the queue that are related to this window
+        // MAYDO: the right way would be to arguably terminate the event thread with the destroy event 
+        // instead of an out of band flag. But order of destruction would have to be checked for a bit of everything.
+        XSync(_display, false);
+        XEvent event;
+        while(true)
+        {
+            Bool found = XCheckWindowEvent(_display, _windowID, windowEventMask(), &event);
+            if (!found) break;
+        }
+
+        unlockX11();
     }
 
     // this frees _graphicImage