#386 Fix SDL sound under FreeBSD

[Rene Ladan]

At least on FreeBSD, SDL sound only works if the sample size is a power of two. If not, an message appears and Fuse stays silent.

"fuse: error: Couldn't open sound device: Fragment size must be a power of two"

Tested with Fuse 1.3.3 and libspectrum 1.3.2 and sdl 1.2.15

Originally submitted by wulf@mail.mipt.ru in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=183694

[Rene Ladan]

Sorry, first patch didn't came through as I was testing a bit.

[Fredrick Meunier]

Hmm, that's weird - do you know where the underlying requirement for the power of two fragments comes from (so we can detect it more specifically as it doesn't seem to be a SDL requirement as such)?

We used to have power of two fragments for Amiga-related platforms - does the attached patch also work for FreeBSD?

[Rene Ladan]

I tested your patch on my laptop (running a development version of FreeBSD), it works fine there. I also build-tested it against FreeBSD 10.3-RELEASE and 11.0-RELEASE for x86 (32-bit and 64-bit) and armv6 (Raspberry PI) platforms.

[Rene Ladan]

I didn't look into the underlying reason for the "power of 2" requirement yet.

[Fredrick Meunier]

Thanks for the feedback, proposed patch applied for the next release.

I'd still be nice to know whether the requirement comes from a specific underlying sound software stack like OSS.