[nas] audiolib: unexpected async reply...

[Jon Trulson]

On Sun, 28 Jan 2001, Erik Inge Bolsø wrote:

> Date: Sun, 28 Jan 2001 19:11:00 +0100 (CET)
> From: Erik Inge Bolsø <knan at mo.himolde.no>
> To: nas at radscan.com
> Subject: [nas] audiolib: unexpected async reply...
> 
> Greetings.
> 
> After the addition of mixer emulation to libaudiooss, I've started getting
> in trouble with xmms. I suspect I'm stressing something too hard, due to
> xmms' constant open->read->close mixer cycle several times a second.
> 
> symptom:
> "audiolib: unexpected async reply (sequence 0x110)!"
> 

	Ahh... Threading...  The issue here is that libaudio and (probably
libaudiooss) are not thread safe.  Bummer.  libaudio has calls to
Lock/Unlock itself during protocol requests/replies, but I notice that
they are currently defined as no-ops.  The issue you are probably seeing
is that libaudio received a reply for a protocol request it doesn't think
it made (another thread probably did that).  You can also get 'lost
sequence' errors in these cases too.

> Is this an unrecoverable error? If not, how do I recover from it?
> 

	It's usually not (reliably) recoverable, since once the protocol
reply is sent, it's not sent again, so depending on what protocol request
was sent, the library could hang if it doesn't get an expected response... 

	I'll add that to the ever growing TODO list ;-)

[...]

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Jon Trulson    mailto:jon at radscan.com
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