alsa-project/alsa-lib issue #219 was opened from mpeter50:

When I'm on Windows, I sometimes use the line-in Jack to connect my phone to it, so I can either listen to it's sounds along with my PCs sounds or use it as a microphone.

I've tried to set this functionality up on my Linux installation, but it seems something is not right. The most basic example is with `arecord`: after setting line-in as the default input device with `alsamixer` I've ran `arecord -vv -fdat foo.wav` so I can check what the ALSA drivers actually "hear" without possible interference of any audio servers. While the command was running, I changed the volume of line-in using he appropriate slider of pavucontrol. When playing the recording, it is clear that while line-in is at 100%, the sound is so loud that it is distorted, and the normal volume is around 12-15% of the actual volume.

I don't experience this on Windows, so this is probably not a hardware issue. If I plug a headphone directly into my phone and listen to it, the volume is normal, so this is probably not an issue on the signal producer side either. Checking with `alsamixer`, all capture controls are at 0 volume. But, the controls there might not tell the full truth for multiple reasons: - after reducing the Capture control's volume I can still hear the sound coming from line-in - the Capture control's volume is not in sync with what I see in pavucontrol and other places like KDE's volume menu - the controls Master and PCM in the Playback category does not seem to have any effect. As such, none of the controls control the actual output to my headphone - the "default" card has a single slider, it is named Master and this actually controls the master volume, at least for my headphone

Screenshot relevant to the 1st and 2nd points:


Additional information: - output of the alsa-info script: [alsa-info.txt](https://github.com/alsa-project/alsa-lib/files/8327703/alsa-info.txt) - Content of `/proc/asound/card*/codec#*` files: - [/proc/asound/card0/codec#0](https://github.com/alsa-project/alsa-lib/files/8327730/card0_codec0.txt) - [/proc/asound/card1/codec#0](https://github.com/alsa-project/alsa-lib/files/8327735/card1_codec0.txt) - note: card0 is the HDMI section of my graphics card. I never use it for audio, only jack and bluetooth, so it can probably be ignored - output of `lspci -vvnn`: [lspci.txt](https://github.com/alsa-project/alsa-lib/files/8327777/lspci.txt)

Issue URL : https://github.com/alsa-project/alsa-lib/issues/219 Repository URL: https://github.com/alsa-project/alsa-lib