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#1 2019-05-13 20:13:07

saymonz
Member
Registered: 2017-02-19
Posts: 7

PulseAudio / HDA : incorrect output mapping

Hi there!

So I run Arch on a MSI GT73VR laptop, it has a Intel HDA audio chipset (ALC898) with an integrated "Sabre Hifi DAC" for the headphones output.

The laptop have :
- 2 integrated speakers
- 1 Headphone Out Jack that can be used as a SPDIF output (mini-TOSLINK)
- 1 Mic In
- 1 Line In
- 1 Line Out

Issue is when I plug my headphones in the dedicated Jack, Pulseaudio switches to the corresponding Headphones output and no sound comes out. If I manually select the SPDIF output, sound plays in the headphones. My guess is that what PulseAudio (or ALSA? Which one does this?) sees as SPDIF Output is in fact directed at both the DAC for analog jack output and the SPDIF port, so it makes sense that at the driver level it is a digital output. I don't have a mini-TOSLINK cable to check though.

I wonder what is the correct solution to seek: should I remap the HDA jacks with HDAJackRetask? I tried to do this but fixing the Headphones made the speakers works bad (outputting only on the third "bass" speaker on the rear). I failed to find easily understandable documentation on HDATaskRestask. Or maybe should I find a way to reconfigure PulseAudio to consider the SPDIF Output as the Headphone Output? PuleAudio configuration files are a bit obscure too, any help appreciated.

I also found that some guy at System76 proposed a patch to the ALSA drivers to support a similar setup (ALC898+DAC) on their laptops, but it seems it was never merged? So maybe it should be seen as a bug in ALSA-drivers? I even tried compiling a custom kernel with this patch, had to make some adjustments based on my limited comprehension of the code, no effects but I'm surprised it even compiled tbh.

alsa-info.sh ouput: https://pastebin.com/Rs8QwNnD
Relevant topics discussing issues on similar if not identical hardware :
- https://bbs.archlinux.org/viewtopic.php?id=219383
- https://bbs.archlinux.org/viewtopic.php?id=229296

Any help appeciated smile

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