09-08-2015, 05:21 AM
I found the problem was with video card. I have Intel 5500 IGU + GeForce 820M. I installed bumblebee + nvidia346 driver from the repository and now there is no problem of any kind. I am even able to put the laptop on sleep and lock screen and everything else. Earlier sound also used to get stuck for 4-5 secs but now it's gone too.