Subject: Re: i386 sound drivers.
To: Herb Peyerl <>
From: Brad Kidwell <>
List: current-users
Date: 07/31/1995 09:10:33

I'm using a NetBSD -current machine with two Soundblaster Pro cards for
full duplex operation.  It uses post July 8, 1995 SB drivers.  I haven't
noticed the particular problem you were describing.  However, when
opening /dev/audio and writing to it; I find that if the file size is
larger than 8000 bytes, than I can have problems.  Specifically, if I'm
reading sound packets from the network which are less than 8000 bytes,
and then trying to write them to /dev/audio, I get only silence,
although the write() returns the correct byte count.  I've found the
only way to solve this is to do an ioctl(AUDIO_FLUSH) which basically
reinitializes the drivers buffers and disables a DMA flag.  I have this
suspicion that the driver is pausing on the DMA flag, and just
overwriting its buffers, without flushing the buffer to the audio card. 
Other than this, it works normally.  Earlier, I had tried to use a
Gateway 2000 SB "compatible" card.  It did playback, but didn't record.

/Brad Kidwell                  
/Information Networking Institute                            /
/Carnegie Mellon University  Office: (412) 268-8128, 268-3029/   
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/"God help us we're in the hands of engineers."		     /
/          -Jeff Goldblum as Dr. Ian Malcolm in Jurassic Park/