DSOUND: prevent assertion in mixer.c

[Alex Villací­s Lasso]

Felix Nawothnig wrote:

>
>> Since the error of "length not a multiple of block size" is nonfatal, 
>
>
> Yes it is fatal. Errors mean that something which should not have 
> happened did happen - and we're not talking about something the API is 
> supposed to handle... there is wrong code in Wine, internal states 
> might have gone corrupted and you can no-longer be sure that Wine is 
> working correctly.
>
> The difference to an assert() is that it's probably possible to repair 
> the corrupted state but there is no guarantee for that since the error 
> might be caused by completly unrelated code.
>
> And this is exactly what we you do in your code - you dunno the reason 
> why mixpos became greater than buflen but you know how to handle it, 
> that's why you should put an ERR there.
>
Hmmm... I have a moderate collection of Japanese RPG games, for the sole 
purpose of testing them under Wine, and most, if not all of them 
reliably display the "length not a multiple of block size" when I run 
them. This error looks now more serious than I thought at first. I 
really need to look into it.

When I said "nonfatal", I meant that the error does not force the 
program to terminate. I meant nothing about the seriousness of the error.

>> unlike the assertion, I submitted the patch as it is. I will need to 
>> read more of both DirectSound and the source code in order to 
>> understand the implications of the non-multiple error, since there is 
>> another game from the same source (LittleWitch/FloatingFrameDirector) 
>> that displays the same non-multiple errors without triggering the 
>> assertion. What kind 
>
>
> In the game I tested the assertion failure was not really 
> reproducable, sometimes I played through the whole game (a demo) 
> without problems - it also seems to be timing related...

In the game I tested, the assertion happened at the exact same point 
into the game (the shot of the girl in the water tank). I provided the 
link to the problematic demo along with the patch 
(http://www.littlewitch.jp/sirotume.exe). BTW, all the tests I do are 
made with the ALSA driver. The other drivers do not exercise the code I 
am trying to debug in DirectSound.