This is aimed at latitude e7440 owners who have sound issues.
I have had two e7440's. Both had sound issues. When I would plug in a headset or a headphone into the 3.5 millimeter headphone jack, it would take upwards of 3 - 5 seconds for it to be recognized and switch from the external speakers to the headphones. Occasionally, it would fail to switch and the audio port would never truly "turn on" and no sound would play despite a headphone being plugged in. I chalked this up to a driver issue (dell audio) or just an annoying characteristic of the laptop.
About a week ago the switching stopped working. I would plug a pair of apple earbuds into the headphone jack and no popup to choose a headphone type through dell audio would popup. The sound would play through the external speakers, no matter what I did.
I googled my issues and came across this thread:
http://en.community.dell.com/support-forums/laptop/f/3517/t/19587903
Which provided me a solution. My audio daughter board had failed. I got it switched out today as my unit is still under warranty. And lo and behold, when I play music, the headphone jack plays the music instantly. No delay at all in recognizing the input.
So, if your latitude e7440 has trouble recognizing your when you plug in your headphones into the 3.5mm headphone jack, and it takes ages for it to "switch", your daughter board is faulty is it will fail soon. Get it replaced ASAP while your unit is still in warranty.
Now all we have to do is fix the "shut down while in sleep mode" issue I'm sure you all have noticed and have. [:'(]