MSGID: <10dejui$293ep$1@dont-email.me> f10bb2df
REPLY:  21d12af7
PID: PyGate 1.5
TID: PyGate/Linux 1.5
CHRS: CP1252 2
TZUTC: 0100
REPLYADDR tnp@invalid.invalid
REPLYTO 3:633/10 UUCP
On 23/10/2025 19:09, Adrian wrote:
> Pi3 running Bookworm.
> 
> I have a python program that runs continuously, that will when it 
> detects an event call aplay to play a short tune.
> 
> This has been working fine, until today.ÿ I had to reboot the Pi earlier 
> today, and now the python won't play aplay (the python is running as it 
> logs when the event happens).
> 
> If I do a cut and paste of the aplay command, it works fine.ÿ So the 
> problem looks as though it is some thing to do with the python call. 
> Both command line and python are running under the same user.
> 
> What I'm seeing logged by the python code is the following error :
> 
> ALSA lib pcm_dmix.c:999:(snd_pcm_dmix_open) unable to open slave
> aplay: main:831 audio open error: Unknown error 524
> 
> I've tried rebooting again, and an Internet search doesn't come up with 
> anything for my particular problem (they all seem to be "nothing working").
> 
> Any suggestions on what to hit with the big hammer ?
> 
> TIA
> 
> Adrian
I had issues like this that were in the end permissions, although in 
this case its hard to see how this happened.

Are you running an audio hat? check its well plugged in

-- 
?But what a weak barrier is truth when it stands in the way of an 
hypothesis!?

Mary Wollstonecraft


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