[L2Ork-dev] Purr Data: File / Print... PDF

[Jonathan Wilkes]

On Fri, Oct 23, 2020 at 3:36 PM Albert Graef <aggraef at gmail.com> wrote:
>
> On Fri, Oct 23, 2020 at 6:46 PM Jonathan Wilkes <jon.w.wilkes at gmail.com> wrote:
>>
>> Regardless, the problem is that this is a blocking javascript call. So
>> it won't matter where you make the call from.
>
>
> Ok, I see. Somehow I assumed that JS had some form of multithreading, which it doesn't. So any kind of JS code that executes for some time will cause this issue.
>
>> However, the dialog that pops up for sending a message to pd is also
>> blocking. Does that cause the backend to hang up as well?
>
>
> Yep, exactly the same thing, on Linux at least. After running File/Message (Ctrl+M), the watchdog signals exactly two times, then I get that SIGHUP in the select() call. On the command line it prints:
>
> watchdog: signaling pd...
> watchdog: signaling pd...
> recv: Interrupted system call (4)
>
> The only way to prevent that is to use Jack as the backend. (Which is what I normally do on Linux, therefore I've never noticed this bug before.) With Jack the watchdog keeps signalling while the JS callback is running, but no SIGHUP, so everything goes back to normal once the JS callback is done executing.
>
> It doesn't happen on Mac or Windows either. So it looks like this is actually tripped by something in the (ALSA/OSS) audio backend code on Linux. It doesn't matter whether DSP is on or off either, and even happens if no ALSA/OSS devices are configured at all.
>
> I see that there are some fairly recent code changes in sys_domicrosleep() in vanilla, though. I'll port those and see whether that helps.

I don't think they will help. The problem is that if pd-watchdog
doesn't receive an acknowledgement it will shut down the backend.

We can change the "message" dialog to something that doesn't block the
js engine. I'm not sure about the print dialog, though.

-Jonathan

>
> Albert
>
>>
>> -Jonathan
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>
>
>
> --
> Dr. Albert Gr"af
> Computer Music Research Group, JGU Mainz, Germany
> Email: aggraef at gmail.com, web: https://agraef.github.io/
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