Re: [fluid-dev] Subversion checkins

[Josh Green]

On Mon, 2007-09-17 at 23:42 -0500, David Hilvert wrote:
> On Mon, 17 Sep 2007 23:38:24 -0500
> David Hilvert <address@hidden> wrote:
> 
> > ==26661== Thread 2:
> > ==26661== Invalid read of size 4
> > ==26661==    at 0x4078F14: fluid_synth_dither_s16 (fluid_synth.c:1824)
> > ==26661==    by 0x4056651: fluid_alsa_audio_run_s16 (fluid_alsa.c:558)
> > ==26661==    by 0x40F42D2: start_thread (in /lib/libpthread-2.6.1.so)
> > ==26661==    by 0x4BFE2FD: clone (in /lib/libc-2.6.1.so)
> > ==26661==  Address 0x5571C88 is not stack'd, malloc'd or (recently) free'd
> > ==26661== 
> > ==26661== Invalid read of size 4
> > ==26661==    at 0x4078F4B: fluid_synth_dither_s16 (fluid_synth.c:1828)
> > ==26661==    by 0x4056651: fluid_alsa_audio_run_s16 (fluid_alsa.c:558)
> > ==26661==    by 0x40F42D2: start_thread (in /lib/libpthread-2.6.1.so)
> > ==26661==    by 0x4BFE2FD: clone (in /lib/libc-2.6.1.so)
> > ==26661==  Address 0xC4BD8AE0 is not stack'd, malloc'd or (recently) free'd
> 
> It seems as though, rather than dither_index being trampled on, the synth
> pointer might be bad.  Is the pointer value (and its initialization, etc.)
> thread-safe?
> 

I just discovered what is wrong.  Mystery is, I don't see how it would
work at all on any system with meters enabled in QSynth.

Seems some of the audio driver re-working I did caused the problem.  The
new_fluid_audio_driver2 does not require a synth instance in order to
function, since the callback function is responsible for rendering the
audio.  Somehow I overlooked this fact and assumed that the data
parameter was the Synth, when in the case of QSynth its actually its own
internal synth class.

I'll have to think more of how to fix this problem though, since now
that the 16 bit dithering is used, there are some variables in the synth
instance that need to be accessed even in the case of the audio callback
method.  Probably won't be until later this week when I can get to it.

Thanks again for all the probing!

        Josh