[KMS] Noise over HDMI every 10 seconds

[BobOmbuzal]

Disclaimer: I'm not sure if it is a bug. But it's annoying.

PI: Raspberry Pi 3 Model B Rev 1.2
OS: Debian GNU/Linux 11 (bullseye)
KERNEL: 6.1.21-v8+

in config.txt

hdmi_group=1
hdmi_mode=5
camera_auto_detect=0
display_auto_detect=0
dtoverlay=vc4-kms-v3d
max_framebuffers=2
arm_64bit=1
gpu_mem=256
dtoverlay=disable-wifi
dtoverlay=disable-bt
dtparam=audio=off

Here is the setup:
raspi3b.hdmi.out -> tv.hdmi.in -> tv.analogaudio.line_out -> stereo.line_in -> speakers

Well everything works as expected, video (mpv) playing on the TV via HDMI, the audio goes through the TV to the stereo via analog audio line cable (cinch), and to the speakers.

But i noticed that every 10 seconds there is a 'TZZK' noise in the speakers.
(I hear it while nothing is playing, volume turned up)
It definitely comes from the pi, when i turn it off the noise is gone.
When i switch from kms to fkms (dtoverlay=vc4-fkms-v3d), it's gone too.

It sounds like at boot time when the resolution is switched/console font is loaded. 'tzzk'

Is there a thing/an event that happens every 10s via HDMI just on the kms that could cause this?
If yes is there anything 'we' can do about it?
It's probably fixable with a SPDIF audio instead of analog, but i don't have that.