[Fwd: WINE: suspected bug in change to winealsa.drv/waveout.c]

[Deomid Ryabkov]

Maarten didn't reply, widening to wine-devel@

summary: looks like a bug was introduced into WaveOut queue management 
back in october
that causes sound to skip and stutter.

-------- Original Message --------
Subject: 	WINE: suspected bug in change to winealsa.drv/waveout.c
Date: 	Sun, 25 Jan 2009 03:46:09 +0000
From: 	Deomid Ryabkov 
To: 	[e-mail]

hi, Maarten.

i'm a complete noob in WINE, this is the first time i delved in the 
source, so please bear with me if i'm wrong,
but i believe i traced a specific problem i've been having with sound in 
Heroes of Might and Magic III
to a change you made couple months ago to the ALSA waveout driver.

the regression manifests itself as rather annoying audio skipping and 
stuttering.
having spent some time tracing and looking at the code, i believe that 
the problem
was introduced by this change to dlls/winealsa.drv/waveout.c made on Oct 4:

http://source.winehq.org/git/wine.git/?a=commitdiff;h=717df5b2972b3cb998ca5a...

specifically, this line

+        wwo->dwPlayedTotal += lpWaveHdr->reserved - wwo->dwPlayedTotal;

advances the dwPlayedTotal watermark when i believe it shouldn't.
fundamentally, only DSP can report how much has been played, updating 
this pointer after reporting
that a sample has been played makes no sense. DSP has reported that it 
has played
up to a certain point that covers the sample in question, we are 
reporting this back and removing the sample.
we should *not* be changing the value DSP sent us.

i don't know what was the specific issue you were addressing with the 
patch in question,
but i'd like you to take one more look at it, because removing this one 
line fixes skipping and stuttering for me.
if you need any more information, please feel free to ask.