Another Wine OSS hang-at-end-of-playback bug

[Matt Chapman]

Hi,

I'm seeing some apps hang after playing an audio sample (even after
the latest fix from Eric Pouech/Dan Kegel).  I've tracked it down
to the following.

dwBufferSize is calculated from info->fragstotal * info->fragsize:

   wwo->dwBufferSize = info.fragstotal * info.fragsize;

whereas dwPlayedTotal is calculated using info->bytes:

    wwo->dwPlayedTotal = wwo->dwWrittenTotal
                          - (wwo->dwBufferSize - info->bytes);

Thus the assumption is that, at beginning and end of playback,
info->fragstotal * info->fragsize == info->bytes, so that
wwo->dwPlayedTotal == wwo->dwWrittenTotal.

But, for my soundcard (ymfpci driver), after asking for 15 frags *
1024 bytes the situation is:

    fragments = 15, fragstotal = 18, fragsize = 1024, bytes = 15612

i.e. info->fragstotal * info->fragsize = 18432, info->bytes = 15612

Thus dwPlayedTotal never reaches dwWrittenTotal and the last buffer
never gets marked as done.

Using info->bytes for wwo->dwBufferSize does fix my problem, not sure
if there's a better solution.

Matt

[Looking at the driver, it looks like the difference is a safety
margin to stop the DSP when it reaches the end.  Arguably the driver
should just report 15 in fragstotal and not bother applications with
the detail that its buffer is actually 18 frags in size...]


Index: dlls/winmm/wineoss/audio.c
===================================================================
RCS file: /home/wine/wine/dlls/winmm/wineoss/audio.c,v
retrieving revision 1.68
diff -u -r1.68 audio.c
--- dlls/winmm/wineoss/audio.c	15 Dec 2002 02:59:13 -0000	1.68
+++ dlls/winmm/wineoss/audio.c	28 Dec 2002 09:56:46 -0000
@@ -1357,7 +1357,7 @@
 
     /* Remember fragsize and total buffer size for future use */
     wwo->dwFragmentSize = info.fragsize;
-    wwo->dwBufferSize = info.fragstotal * info.fragsize;
+    wwo->dwBufferSize = info.bytes;
     wwo->dwPlayedTotal = 0;
     wwo->dwWrittenTotal = 0;
     wwo->bNeedPost = TRUE;

[Eric Pouech]

Matt Chapman wrote:
> Thus the assumption is that, at beginning and end of playback,
> info->fragstotal * info->fragsize == info->bytes, so that
> wwo->dwPlayedTotal == wwo->dwWrittenTotal.
>
> But, for my soundcard (ymfpci driver), after asking for 15 frags *
> 1024 bytes the situation is:
>
> fragments = 15, fragstotal = 18, fragsize = 1024, bytes = 15612
>
> i.e. info->fragstotal * info->fragsize = 18432, info->bytes = 15612

this sounds a bit crazy from the API point of view
but if the driver is really implemented like this your patch would be 
fine. IMO, we should anyway add a comment for this behavior in the code 
so that we don't loose track of this interesting "feature"

-- 
Eric Pouech