Can't adjust audio output volume of Steam Machine

[vicnett]

Your system information

• Steam client version: 1782861641
• SteamOS version: 3.8.14
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes

Please describe your issue in as much detail as possible:

Describe what you expected should happen and what did happen.

When plugged into my TV via HDMI, I expect to be able to adjust the audio volume via slider in the quick access menu, just like with a docked Steam Deck.

Instead there are three volume-related buttons: plus, minus, and mute. None do anything for me. Plus they are labeled "TV volume" which would suggest that if they worked the buttons would control my TV's volume directly.

That is probably the issue: I have a sound bar connected to my TV's line output so no volume controls on the TV do anything.

I wouldn't want it to adjust my TV volume anyway; I need to be able to set the Steam Machine volume independently. I use my TV for other things too, and if I can set all audio sources' volume independently I can get them all to a consistent volume so I don't have to fiddle with it all the time.

As it stands, if I watch YouTube (primary use of the TV) then switch to the Steam Machine, everything is extremely loud. Then when going back to YouTube, everything is super quiet.

Docking a Steam Deck gives the expected experience (an independent volume slider).

Steps for reproducing this issue:

1. Use Steam Machine normally with a TV via HDMI
2. Optionally use the TV line output for audio
3. Note the lack of audio slider in the quick action menu and the ineffectiveness of the TV volume control buttons if using line audio