Ardour5 crashes suil error


I’ve just downloaded official build (and removed the one given in Fedora repository) to check if that version fixes my drumkv1 plugin problem.

The non-official build from repository displayed a black rectangle.

The official one crashes with that error

Now connected extension is required
suil error: Unable to open UI library /usr/lib64/lv2/synthv1.lv2/ (/usr/lib64/ undefined symbol: hb_font_funcs_set_font_h_extents_func)
Segmentation fault (core dumped)

This is the last Ardour5 version, I didn’t checked with 6.* versions.

I installed suil, suil-devel, harfbuzz and harfbuzz-devel, whatever I do, the plugin crashes Ardour5.

It seems that I’m not the only one here to have that problem (I don’t find the post I’ve seen minutes ago for a Arch user, I’m on Fedora and the problem exists for me too).

I did many tests, Calf plugins are displayed. The problem exists for drumkv1 and synth1 plugins AFAIK.

Thanks for you help.

The issue at hand is the plugin pulling in system-wide libs (here: QT and QT’s dependencies) that conflict with Ardour. The solution would be to make the plugin self-contained, no depending on external libs.

A longer explanation about the issue is e.g. – the issue has also been discussed various times on the LV2-devel list e.g.

In the not too distant future we will likely drop support for QT GUIs (and GTK plugin GUIs) and only support native UIs and self-contained plugins that do not depend on external libraries.

Calf and guitarix are moving away from gtk as we speak (using

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That was what I understood. Thanks for explanations :wink:

after spending some time with the developer of the *v1 plugins and we users now have available access to this document to help make the case - – rncbc now makes his v1 plugins static-built. When users have issues like this, we need to be a little more brave into also contacting the plugin developers so that things can be looked into from their side. Glad you pointed this out, but this only became resolved one year later when the plugin developer was finally contacted… (ardour will not contact the plugin developers and leaves this for the end-user). Understanding is the first step, contacting the plugin developer is the next… and it got fixed so everyone is happy. :slight_smile:

if we have a similar problem like this again, we users need to step-up into contacting the plugin developer otherwise plugins that are external of the ardour project never get fixed.

Ardour has its own project plugins, but that doesn’t mean they will contact external plugin makers, that’s the job of the end-user…

If you’re looking for the build-change that has the statically-build fix, the edition of the v1 plugins should be dated around the end of october …

0.9.11 2019-10-31 A Halloween’19 Release.

- Upstream packaging is now split to JACK standalone and
LV2 plugin only: the former shared common core and UI
package is now duplicated but statically linked though.

Requesting of the 0.9.11 release builds should now be available for their static-link fix.


Not quite. For the issue at hand I spent quite some time with Rui, and we’ve discussed this at the Linux Audio Conference along with other devs. We also reach out to other vendors, including some proprietary ones. softube is one example. Since they were able to read our source-code they even managed to identify the issue and help fix it.

Still contact by end-users has more impact and we very much welcome that! Thank you for going the last mile motivating Rui to provide self-contained plugins!

PS. To clarify things: The plugins-in-process document that you link to is unrelated, in particular since LV2 allows for process separated UIs. The issue at hand is caused by library ABI incompatibilities, specifically libsuil that bridges between Ardour (gtk2, bundled libs) and plugin UIs that rely on system-wide libs.