Mageia 7. I discovered this only recently, when due to shutdown have to use headphones. Output sound works perfectly, but input microphone in muted and cannot be activated in pulseaudio (see picture).
Some relevant info from alsa.conf:
Manufacturer: ASUSTeK COMPUTER INC.
Product Name: UN68U
Product Version: To be filled by O.E.M.
Firmware Version: 0412
Board Vendor: ASUSTeK COMPUTER INC.
Board Name: UN68U
-----------------!!Soundcards recognised by ALSA
0 [PCH ]: HDA-Intel - HDA Intel PCH
HDA Intel PCH at 0xf7340000 irq 147
!!PCI Soundcards installed in the system
00:1f.3 Audio device [0403]: Intel Corporation Sunrise Point-LP HD Audio [8086:9d71] (rev 21)
Subsystem: ASUSTeK Computer Inc. Device [1043:864d]
ARECORD
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: CX20751/2 Analog [CX20751/2 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
Trying searching online gave no help. I do not think it is a bug, just my unability to get the system working. On my ASUS laptop everything is OK.