White noise from headphone jack.

I have the Dell Latitude E5540 with Ubuntu 20.04 and whenever I use headphones that plug onto audio jack I hear a hissing/static sound. I hear the same sounds using the speakers.

Solution

Open Terminal (CRTL + ALT + T) and past the command 

1. Verify how is your sound card's power_save parameter:

   cat /sys/module/snd_hda_intel/parameters/power_save
   

2. If it returns 1, do the following to change it temporally:

   echo "0" | sudo tee /sys/module/snd_hda_intel/parameters/power_save
   

3. If the previous step worked for you, persist that configuration (otherwise the problem will continue after reboot):

   echo "options snd_hda_intel power_save=0" | sudo tee -a /etc/modprobe.d/audio_disable_powersave.conf
   

4. (Optional) You can also do the same for power_save_controller parameter following the steps 1, 2 and 3 replacing power_save by power_save_controller also changing 0 to N.

   Note: using the first step will probably return Y for this parameter, instead of 1.