How do I enable CD-in?

I managed to get the CD slider to show up in alsamixer. This is based on the description found at http://www.spinics.net/linux/fedora/alsa-user/msg11769.html

First, create a file /lib/firmware/hda-init.fw with the following contents:

[codec]
0x10ec0888 0x14627522 0

[pincfg]
0x1c 0x993301f0

These are the values for my mainboard. I am assuming that they are identical for yours if you are also using the Realtek ALC888 codec. You can find these value by using the alsa-info.sh script. Your output should contain something like this:

!!HDA-Intel Codec information
!!---------------------------
--startcollapse--

Codec: Realtek ALC888
Address: 0
AFG Function Id: 0x1 (unsol 1)
Vendor Id: 0x10ec0888
Subsystem Id: 0x14627522

The numbers from Vendor Id and Subsystem Id are the ones that need to go in the file we created above under the [codec] line.

I have no idea what the [pincfg] line actually does and what those numbers are but it seems to work.

Once you have created that file we need to tell ALSA to read it. Open /etc/modprobe.d/alsa-base.conf and add the following line at the end of the file:

options snd-hda-intel patch=hda-init.fw

Now the CD slider should show up after reloading ALSA. However, this did not work for me. Restarting my machine, however, did fix it.

Now you can just use the ALSA mixer to crank up the CD volume and you should hear the sound on your speakers.

Note that at least on my machine the CD slider seems to be muted by default. You will be able to set the CD volume but you will not hear anything unless you unmute it. To do that press M and you should hear the sound.