In i3wm of Linux laptop, you have to use terminal application
(here we choose alsamixer) to control sound device.
It's a preinstalled app on Mint 18.04.
Install it with sudo pacman -S alsa-utils on ArchLinux.
Run alsamixer and a TUI window appears.
The "Card" value on the left-upper corner is "HDA Intel HDMI", which is not the
current used device. Press F6, a list appear:
- (default)
0 HDA Intel HDMI
1 HDA Intel PCH
29 ThinkPad Console Audio Control
This means there are totally 3 playback devices. And currently "0 HDA Intel HDMI" is the default one. The right audio output device should have "dB gain..." in its "Item" value. If we choose "1 HDA Intel PCH", on the upper-left corner there will be a line: "Item: Master [dB gain: 0.00]". So this is the right one, and its id is "1".
In window of this device, tab to "Master", use "m" key to toogle its status from "MM" (means mute) to "OO" (means open this device). Then use up arrow key to increase its volume, until the "dB gain" is zero.
Quit it with "ESC" key. Create a new file ~/.asoundrc:
defaults.ctl.card 1
defaults.pcm.card 1
Now test it with speaker-test -c 2.
Ref: "No sound when S/PDIF video card is installed" section in Advanced Linux Sound Architecture.