[Bug 21589] MacOS error from MIDI SetVolume

http://bugs.winehq.org/show_bug.cgi?id=21589

--- Comment #2 from Jörg Höhle  2011-01-13 05:53:00 CST ---
commit 2e54019391572d354d9a3295ee941df3cb536897 fixed a) the fourcc message

b) is about the typical tension between
 - be internally consistent: given no support for XYZ in Wine, e.g. volume,
   don't set the corresponding capabilities flag, e.g. MIDICAPS_VOLUME;
   (somehow figure out good error code to return)

- lying to the app and pretend volume is supported, presumably because
   that's always the case in native (or native always lies as well?)
   and apps behave badly when presented fewer flags;
   possibly add FIXME() + stub message

- going to extra hoop to match both sides, e.g. add a volume filter
   into the MIDI audio chain (which only makes sense with a SW synth).
   This would be superfluous with PulseAudio which already provides easy
   per app volume control, but I've not seen that for MacOS' SW-synth.

BTW, the native MIDI volume setting is tied to the audio/mixer control panel in
system preferences when the SW synthesizer is in use.