"Turn" Ubuntu under the voice headphones no sound

Really use Linux every day there are new discoveries ah, this morning with a computer, want to listen to a few songs, plug in headphones found no sound, I thought it was the headset is broken, put the headset in the phone, found that the headset has a voice, very puzzled, I like the computer interface has a problem, but in the system when the headset will ring, So should not be the interface problem, and then check the computer audio settings and drivers, found that the appropriate, I have the computer restarted a bit, found or not, very dog blood is I put the computer together, and then open, very magic has a voice, and I do not understand why, I would like the computer combined state is what, Turn on power management, found closed computer cover is suspended, briefly say Ubuntu hangs, suspend instruction halt execution, kill application process, perform sync system call, file system write operation will stop the kernel, when the user can directly shut down the power, hangs the hard disk, The current state of the computer is loaded into memory, that is, the hard drive is powered off, but the memory is still powered. The advantage is that the recovery is fast, the disadvantage is to keep the power supply, power outage will have to restart. Hibernation is to save the current state of the system to a dormant file in the hard disk, and then all the devices shut down, you can safely turn off the power, the next restart, will automatically call the hard disk saved files, restore to the state before the shutdown. The advantage is that power is not required and can sleep for a long time, with the disadvantage of slow recovery (relative to hang). Suspend recovery as long as 2, 3 seconds, soon. Sleep recovery takes more than 10 seconds, slower than hang, but a lot faster.

"Turn" Ubuntu under the voice headphones no sound