Sound only out of internal speakers, never headphones (Alienware laptop, Ubuntu 15.10)
Solution 1:
I found the solution somewhere. Do the following:
In terminal, enter the command "alsamixer".
An ASCI UI will open, use the arrow keys to find the item: "HP/speaker Auto Detect". it will say "Off" next to it.
Press M and the "Off" tag will disappear.
Re-plug your headphones.
Enjoy!
Solution 2:
I had exactly the same issue. Apparently the Alienware 17 r3 is comparatively a new model coming out in late September last year so lots of driver issues exist.
FAQ:
Q.Wifi not working?
A.Follow this link to fix Broadcom ath10k(killer wifi) wireless card. https://github.com/kvalo/ath10k-firmware/pull/3 (Note: Your kernel should be higher than the ubuntu 15.10 official image's)
Q.Could not boot and drop to initramfs?
A.If it is the i915 Guc issue, no solution yet since i already tried to update the latest firmware from intel (kernel 4.3.3) but still 'firmware-4.bin'not found issue exists. If it is the ssd not found issue, try to add 'nvme' to: /etc/initramfs-tools/modules and run 'update-initramfs -a'(kernel 4.4.0)
Q.Could not mount!!!Ubuntu will freeze when back to unity login screen because of ssd detached from system i think. Very annoying issue since i have to move my laptop with lid open or choose 'do nothing' option in power setting.
A.No clue yet.
Q.Only internal speaker works?
A.No solution yet.I am now running ubuntu 16.04 daily build and 4.4 kernel but still no sound from my headphones. In about kernel 4.4 rc6 diff, See line 772: https://github.com/torvalds/linux/blob/master/sound/pci/hda/patch_ca0132.c It seems like this issue is marked not urgent or no quick solution yet since no driver source code is provided by Creative. Hopes anyone could contact Creative to help fix this issue.
Other issues:
-Unpredictable lights on/off each time booting into ubuntu, no working light switch control software yet.
-'BTRFS error could not find root 8' if you are using btrfs file system instead of ext4.
Solution 3:
I found a workaround:
I bought this USB Audio Adapter
It didn't work out of the box, even after fiddling with system settings. It was detected, but when I changed voice to default, I got still sound from laptop. I tried changing order of audio device loading (USB Device first), still no result.
It turned out all I needed to do was to open pavucontrol (install it if you don't have it) and set sound to USB Audio Device. It has to be done for all audio programs separately (firefox, spotify, audacity, etc.). After that, plugging in headphones or external speakers causes output to be switched automatically to them.
Here is a more detailed forum thread about it