My PC's motherboard has what I think are the typical six audio ports, on board. The orange, black, grey, light blue, green, pink ones. Realtek on an Asus board.
For my use, for years now, the green and light blue have been the important ones. I have my speakers plugged into green, and that works great. I know that blue is the line-in port. What I have been doing is plugging my laptop into it, via its headphone jack. Then, on my taskbar, I can open the volume mixer and see line-in as an option to control the volume of with a slider - independent of the Speakers and various applications. If I had the volume mixer opened and then plugged my laptop in with an audio cable, it would just pop into the dialog, and I'd be set!
I updated Windows 10 a few days ago... Now my line-in no longer shows up in the volume mixer and sometimes stops working until I navigate in through a horde of sound control panels to finally check something to bring it back.
Here is a screenshot showing some weird in-between state the volume mixer is in. Normally I'd see the Line-In and a cables icon for it. That phantom slider there does nothing to any playback.
Does anyone know how to get this feature back? Has something happened with how Windows 10 treats Line-In? There are a ton of sound property dialogs, but nothing seems to bring back what I used to have worked just fine.
Update: For more context, I'm running Windows 10 Professional, and the update installed was the May 2019 Update.
Feature update to Windows 10, version 1903 Successfully installed on 8/28/2019