Loud audio pop before and after every sound with SPDIF Realtek ALC892

Giskard

I have this issue since I started using my SPDIF audio output. Every time an audio sample is started or stopped, i hear a loud pop. Even with repeated system notifications: "POP sound POP".
The same thing, on analog output, happens only at boot time (I suspect when the audio chip is initialized).
I don't hear any pop noise when I have a constant stream of sound. When playing a sound, it's a bit delayed and I miss the first fractions of second of it.
Could it be that the system is turning on and off the audio device every time a sound is played? Maybe some energy management routine that shuts off the device?
If so, is there a way to prevent this?

vimanuelt

Giskard
This script might be helpful. If it does not work, then we'd need to ask FreeBSD core team to patch the sound driver.

#!/bin/sh
# fix-spdif-pop.sh — Disable HDA power-saving to prevent SPDIF pop noises on GhostBSD

# Must be run as root
if [ "$(id -u)" -ne 0 ]; then
  echo "❌ This script must be run as root." >&2
  exit 1
fi

echo "🔧 Applying SPDIF pop fix to /boot/device.hints and /boot/loader.conf..."

# Add hint.hdaa.0.nopowerman=1 and hint.hdaa.0.gpio_config="0=set" to /boot/device.hints
DEVICE_HINTS="/boot/device.hints"
grep -q 'hint.hdaa.0.nopowerman' "$DEVICE_HINTS" 2>/dev/null || \
  echo 'hint.hdaa.0.nopowerman="1"' >> "$DEVICE_HINTS"

grep -q 'hint.hdaa.0.gpio_config' "$DEVICE_HINTS" 2>/dev/null || \
  echo 'hint.hdaa.0.gpio_config="0=set"' >> "$DEVICE_HINTS"

# Add hint.hdac.0.polling=1 to /boot/loader.conf
LOADER_CONF="/boot/loader.conf"
grep -q 'hint.hdac.0.polling' "$LOADER_CONF" 2>/dev/null || \
  echo 'hint.hdac.0.polling="1"' >> "$LOADER_CONF"

echo "✅ Settings applied. Please reboot the system for changes to take effect."

Giskard

vimanuelt Thank you. I tried it but witout success.

I also changed it ny replacing hint.hdaa.0 with hint.hdaa.1 and hint.hdac.0 with hint.hdac.1, because I found that in my pc hdaa.0 is the NVIDIA audio output and the realtek is on hdaa.1 (sysctl -a | grep hda[a\|c])

Giskard

I found a good workaround. If I disable auto suspend from pulseaudio, it seems that I can prevent the whole audio stack to go into suspend mode, thus avoiding the loud noises upon suspend and resume that I hear through my SPDIF to DAC to Speakers.

The workaround is to comment this line in /usr/local/etc/pulse/default.pa

### Automatically suspend sinks/sources that become idle for too long
load-module module-suspend-on-idle