Hi I just stumble upon your post looking at some other issues, and wanted to let you know I found a fix that works for my M3800. After googling for what seems like forever I found a post that says to run the following two commands as root, and it worked, don't remember where I found it. Hope this helps. hda-verb /dev/snd/hwC1D0 0x0c SET_AMP_GAIN_MUTE 0x5180hda-verb /dev/snd/hwC1D0 0x0c SET_AMP_GAIN_MUTE 0x6180 There was also a python script that did the sane thing but I dont know how to attach files here. Jeff
Hi, I opened a thread in another section and I was told this a more suitable section for my question. I just quote myself, here the original discussion. Hi, I bought this machine thinking that it might supported any Linux distro without many issues and in general it does (well, it seems that the light sensor is not detected), however there's a very annoying problem. When headphones are used, there's constant background noise which goes away only when the audio is muted or when the audio card is disabled to save power. However, I still can hear in a completely silent room some noise when the card is disabled, things are perfect only on mute. Also, when the audio card is disabled, there's a loud and short noise (this last thing happens also on another machine using and Intel audio card). However, there are no issues when Windows is used. Is there a chance to have this fixed, considering that the dev edition is meant to work with Ubuntu? 
XPS 13 (9333) - headphones background noise