Re: [hatari-devel] DMA sound and Falcon

[Thomas Huth <th.huth@xxxxxx>]

Am Mon, 12 Sep 2016 18:17:18 +0200
schrieb Nicolas Pomarède <npomarede@xxxxxxxxxxxx>:
[...] 
> I fixed falcon's crossbar to keep a constant sound rate when changing 
> CPU freq at 8 MHz or 32 MHz.
> 
> What is interesting is that if you change cpu freq while playing a
> sound in "compatible STE dma mode" (for example between 16,8,16,8,...)
> the sound will sometimes be noisy, then it will be clear again, or it 
> will stay noisy all the time and so on.
> 
> This randomness really looks to me as if some variables are
> overflowing or are not correctly reset when computing the "steps" to
> convert from the requested Falcon sound freq to the host sound freq.

Not sure if it is related, but I just ran Hatari through valgrind and
it complained about some unitialized variables in the sound subsystem.
I finally tracked the problem down to SDL_OpenAudio: It behaves
slightly differently with SDL2 than with SDL1.2 - it does not
initialize the desiredAudioSpec.size field anymore, so our
SoundBufferSize contained random values. I fixed that problem now, so if
you've got some spare minutes, maybe you could try your test again to
see if there's a difference?

 Thomas