Allow building with sndio support on more systems than just OpenBSD

[ghost]

Sndio also supports FreeBSD and Linux.

[PhysSong]

Why did you turn off Sndio by default? I think you can turn this on and disable on Windows.

[ghost]

Why did you turn off Sndio by default? I think you can turn this on and disable on Windows.

Done.

I was trying to be conservative and keep the behavior on non-OpenBSD
systems the same as before.

[tresf]

Please do not enable this blindly without some evidence that it actually works. I'll quote #3596:

Initially, I had just enabled RoarAudio (adds sdio.h) so we could test sndio via Ubuntu (via Travis). Unfortunately, RoarAudio won't compile, and it's not just us.

[ghost]

What does sndio have to do with RoarAudio? The claim in #3596 that sndio is only available on OpenBSD is bogus. If you want to test this on Ubuntu install their libsndio-dev package.

Here's a build log from building LMMS 1.2.0-rc6 on FreeBSD with this patch applied: https://people.freebsd.org/~tobik/logs/lmms-1.2.0.r6,2.log

[tresf]

The claim in #3596 that sndio is only available on OpenBSD is bogus.

It's a description, not a claim. The message has since been removed from our stable-1.2 branch.

What does sndio have to do with RoarAudio

Our CI environment uses Ubuntu 14.04 and for that platform libsndio-dev is only provided as a virtual package though libroar-dev, which would not compile at time of adding that comment.

Here's a build log from building LMMS 1.2.0-rc6 on FreeBSD with this patch applied:

Thanks for the log and for the link to the bionic mirror. Please understand this will break builds on any 14.04-based machines that have libroar-dev installed. Broken builds eventually turn into bug reports and/or support questions, so it's sane behavior to guard against them.

At the time of writing this, 14.04 is old enough that most desktop users have moved away from it, so this just needs to be rebased and merged... but before anyone does that...

changed the base branch from stable-1.2 to master 17 days ago

@PhysSong can you explain why this PR was removed from our stable branch? If you have no objections, let's put it back on stable and merge it.

[tresf]

So this compiles and bundles just fine on Ubuntu 18.04.

I have a support question...

If we're going to toggle this on for all distros now, how is this backend used? I've tried rsnd/0 but it doesn't appear to work. The best listing I could find was here: http://man.openbsd.org/sndio#DEVICE_NAMES.

Tagging @devnexen too as he created the original PR which added sndio support.

Also @t6 just an FYI - In Ubuntu 18.04 there's a typo in FindSndio.cmake, probably fixed upstream already, but benign.

CMake Warning (dev) in cmake/modules/FindSndio.cmake: line 29:
  A logical block opening [...] closes [...] with mis-matching arguments.

# cmake/modules/FindSndio.cmake: line 29:

  if(SNDIO_FOUND)
      set(SNDIO_INCLUDE_DIRS "${SNDIO_INCLUDE_DIR}")
      set(SNDIO_LIBRARIES "${SNDIO_LIBRARY}")
- endif(HAVE_SNDIO)
+ endif(SNDIO_FOUND)

[devnexen]

I do not know how it works under Linux but is device naming similar as OpenBSD ? Does not know if it brings a different experience than with Alsa neither.

[devnexen]

I forgot to mention is sndiod installed ?

[ghost]

If we're going to toggle this on for all distros now, how is this backend used? I've tried rsnd/0 but it doesn't appear to work.

For starters disable all other audio daemons. Sndio on Linux needs exclusive access to the audio device when used locally. AFAIK pasuspender should temporarily disable PulseAudio. rsnd/0 is the first audio device (it translates to the hw:0 ALSA device) but it might not be what you need on your hardware. So try rsnd/1, rsnd/2, etc. too.

It might be easier to test this with aucat -i /dev/urandom -f rsnd/1 first (if this works you'll hear some whitenoise, aucat is part of the sndio-tools package on Ubuntu) instead of trying it in LMMS.

[devnexen]

Ok so I built all under debian and seems to work tried couple of seconds with rsnd/0 device in my side.

[tresf]

I forgot to mention is sndiod installed ?

No, it wasn't but I managed to get it to work without it.

Sndio on Linux needs exclusive access to the audio device when used locally. AFAIK pasuspender should temporarily disable PulseAudio.

Thanks and spot-on. sndio works as long as pasuspender prefixes the LMMS command.

For the installed version:

pasuspender -- lmms

For the compiled version:

pasuspender -- ./lmms

For the AppImage version:

pasuspender -- ./lmms-1.2.0-rc6.32-linux-x86_64.AppImage

rsnd/0 is the first audio device

That's perfect, I'm in a VM, so there's only one back-end. Fortunately, once PA is suspended, sndio just works without specifying the device. This is ideal.

So I think this is ready for merge to stable-1.2 if @PhysSong agrees. Thanks for the support assistance. The only downside is we can't ship it with our official AppImage because our build system for 1.2.0 is still 14.04 which doesn't provide the proper library. This will change once we start releasing on newer distros, starting with 1.3.0.

From a performance testing perspective, we ship a very resource intensive demo unfa - Spoken and it starts to under-run on virtual hardware about half through where SDL is able to keep up. This isn't a comprehensive test. We'll have more real-world examples trickle in once this is merged.

[PhysSong]

So I think this is ready for merge to stable-1.2 if @PhysSong agrees

What I was afraid of was that stable-1.2 is on a feature freeze. However, I'd like to listen to opinions from other devs. If they agree on merging into stable-1.2, then I won't block that.

[PhysSong]

This will change once we start releasing on newer distros, starting with 1.3.0.

I think we can add libsndio-dev into our CircleCI docker image.

[tresf]

I think we can add libsndio-dev into our CircleCI docker image.

Sounds good. I still think this belongs on stable-1.2, so you can toggle on libsndio-dev in Cirlce-CI anytime.

[ghost]

Thank you, @tresf!