No sound on HDMI by default on Lenovo T14s using Fedora 37

[Takashi Iwai]

On Wed, 18 Jan 2023 16:30:53 +0100,
Mike FABIAN wrote:
> 
> 
> With a Lenovo Thinkpad T14s (Gen1, Intel version), I tried to get sound
> on the monitor speakers via the HDMI cable.
> 
> It didn’t work out of the box and after a bit of googling I found:
> 
>     https://forums.lenovo.com/t5/ThinkPad-T400-T500-and-newer-T-series-Laptops/T14s-AMD-no-HDMI-audio-on-Linux/m-p/5081195?page=2
> 
> 
> which suggested to put
> 
>     snd_rn_pci_acp3x.dmic_acpi_check=0
> 
> on the kernel command line.
> 
> So I tried this:
> 
> $ cat /etc/modprobe.d/lenovot14s.conf 
> options snd-rn-pci-acp3x dmic_acpi_check=0
> 
> And that did make it work indeed.
> 
> I have no idea what this means and why this makes it work.

The option basically should influence on the driver's behavior whether
to probe the built-in d-mic or not, and it has no direct relationship
with HDMI (supposedly via HD-audio bus), so it's puzzling how this
fixes the problem.

Could you run alsa-info.sh (with --no-upload option) on both working
and non-working cases, and attach both outputs for comparison?


thanks,

Takashi