snd_sfx_play doesn't work correctly with volume 255

[gauauu]

The docs indicate that snd_sfx_play() can take a volume from 0 to 255, but when I set a volume of 255, things start to break in the audio system. The audio effect plays incorrectly, and will not play a second time after that. If I have an ogg file streaming at the time, it starts skipping and stuttering. As soon as I switch the volume to 254 instead, everything works correctly.

This breaks:

snd_init();
sfxhnd_t sfx_powerup = snd_sfx_load("/rd/audio/powerup.wav");
snd_sfx_play(sfx_powerup, 255, 128);

While this works:

snd_init();
sfxhnd_t sfx_powerup = snd_sfx_load("/rd/audio/powerup.wav");
snd_sfx_play(sfx_powerup, 254, 128);

See also this forum post:
http://dcemulation.org/phpBB/viewtopic.php?f=29&t=105061&p=1056366#p1056366