Just now was trying to boot into Windows, by plugged in the HDMI cable, which supports for video only. But then, I rebooted into Linux without plugged out the HDMI cable. Then, it caused no sound in Linux.
Try 1: I killed the pulseaudio, then delete the ~/.config/pulse, and rebooted Linux. Failed.
Try 2: Run alsamixer, turned on everything, and do Try 1 again. Failed.
Then I guessed it was caused by the HDMI cable, which the Windows may assume there is audio, then caused my computer somehow ouptut the audio through the HDMI, even I rebooted into Linux.
Try 3: Plugged out the HDMI, booted into Windows. I checked the audio in Windows. It plays well. Then rebooted into Linux without plugged in HDMI. Yeah! It works. Passed.
Then I found that, though the sound works fine, my headphones doesn’t work. Tried out many methods as I asked in forum.
At the end, it is solved by shutdown, and boot again.
Today, when I updated Arch Linux as usual, then suddenly it brought me to the TTY, which didn’t allow me to change to other TTY (due to NVIDIA graphic card issue which has been attached with my laptop for quite a long time.)
Because I could do nothing, and not sure whether the upgrade was completed, so I made a hard reset.
Then I boot with fallback initrmfs just in case has any error. Luckily, there was no problem to boot.
Then I did a quick check on the database. And found that it was locked. Meaning, I had restarted without finishing the update. This is serious if it happened when upgrading the kernel.
Reading the /var/log/pacman.log, I found that some packages were not updated. Then I just simply did a pacman command, and I got these message,
ldconfig: File /usr/lib/libqca.so is empty, not checked.
ldconfig: File /usr/lib/libQt5QuickTest.so is empty, not checked.
ldconfig: File /usr/lib/libQt5QuickParticles.so is empty, not checked.
Read the forum, the solution to re-install the packages that own these files. So I used pkgfile to search fo the owner of these files. Then, re-installed each packages found.
Then I just made sure all the packages were installed properly with
pacman -Dk #previously is testdb