hdac0: Unexpected unsolicited response from address 0: 00000000

balanga · Thursday at 9:29 PM

Can anyone shed any light on these lines that I found in dmesg:-

Code:

[13] acpi_wmi0: <ACPI-WMI mapping> on acpi0
[13] acpi_wmi0: cannot find EC device
[13] acpi_wmi0: Embedded MOF found
[15] hdac0: Unexpected unsolicited response from address 0: 00000000
[15] hdac0: Unexpected unsolicited response from address 0: 00000000
[15] hdac0: Unexpected unsolicited response from address 0: 00000000
[15] hdac0: Unexpected unsolicited response from address 0: 00000000
[15] hdac0: Unexpected unsolicited response from address 0: 00000000

SirDice · Friday at 9:05 AM

Is this the audio from a video card, or the onboard sound chip? I suspect the video card, which one? And what driver are you using for it?

didal · Friday at 9:43 AM

I have something like that on one machine. I had to put in /boot/loader.conf

Code:

# Prevent message at boot due to Bug #229190:
# 'hdac0: Unexpected unsolicited response from address 0: 00000000'
compat.linuxkpi.i915_disable_power_well="0"

balanga · Friday at 10:03 AM

SirDice said:
Is this the audio from a video card, or the onboard sound chip? I suspect the video card, which one? And what driver are you using for it?

The msg comes from a Lenovo ThinkCentre M73 which I use as a headless file server.

I don't use audio on it, I can't imagine how such a msg got triggered,

Code:

root@M73:~ # pciconf -lv | grep Audio -B2
hdac0@pci0:0:3:0:       class=0x040300 rev=0x06 hdr=0x00 vendor=0x8086 device=0x0c0c subvendor=0x17aa subdevice=0x309e
    vendor     = 'Intel Corporation'
    device     = 'Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller'
--
hdac1@pci0:0:27:0:      class=0x040300 rev=0x04 hdr=0x00 vendor=0x8086 device=0x8c20 subvendor=0x17aa subdevice=0x309e
    vendor     = 'Intel Corporation'
    device     = '8 Series/C220 Series Chipset High Definition Audio Controller'
root@M73:~ #

cracauer@ · Friday at 12:59 PM

Certainly harmless. If it bothers you you can turn off the soundchip in the BIOS.

Phishfry · Friday at 1:09 PM

I see it spammed alot on console during user change. No big deal except it does get in the way. ctl-c doesn't help.

Phishfry · Friday at 1:10 PM

balanga said:
root@

At least hide your identity.

balanga · Friday at 6:00 PM

cracauer@ said:
Certainly harmless. If it bothers you you can turn off the soundchip in the BIOS.

I was just surprise to see such an error given that I am not aware of any process which uses sound.

Phishfry · 2026-08-29T01:56:55+0100

Its baked into the kernel. Disable the module with:

/boot/loader.conf

Code:

hint.snd_hda.0.disabled="1"

My firewall with a similar Xeon C226 chipset was giving me that trouble.

hdac0: Unexpected unsolicited response from address 0: 00000000

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