[pulseaudio-discuss] iec958 (S/PDIF) + USB = 100% CPU usage

[Ismael Farfán]

Hello pulse

I'm not sure if it's a bug or not but, I did google around for about an
hour.

I noticed that whenever I have a device configured with the S/PDIF profile
(iec958), PulseAudio uses 100% cpu (2 threads 50% each)

I have a cheap USB device with optical audio support
Bus 003 Device 011: ID 0d8c:0012 C-Media Electronics, Inc. USB Audio Device
Bus 003 Device 010: ID 0d8c:0102 C-Media Electronics, Inc. CM106 Like Sound
Device

Here's how top looks when anything is grabbing the output, even if it's a
paused video. As soon as I close the tab it disappears from top.
PID   PRI  NI  VIRT   RES   SHR S  CPU%▽MEM%   TIME+  Command
1820   9 -11 2218M 46576 28064 S  51.5  0.1  3h41:07 /usr/bin/pulseaudio
--daemonize=no --log-target=journal
55780  -6   0 2218M 46576 28064 S  50.9  0.1  6:23.43 /usr/bin/pulseaudio
--daemonize=no --log-target=journal

I changed the profile of my USB headphones to use iec958 and I could see
pulseaudio again using 100% cpu even though I only hear noise because the
headphones don't support it.

So my guess is that it's got something to do with the iec958 encoding.

Any ideas?

I'm on Debian stable bookworm with KDE Plasma

Regards


-- 
Do not let me induce you to satisfy my curiosity, from an expectation, that
I shall gratify yours. What I may judge proper to conceal, does not concern
myself alone.
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