I have a dell inspiron 5520 which has a amd radeon 7670m graphic card.
Earlier on 13.10 I used to turn off my graphic card (it generates a lot of heat otherwise) using
$ echo OFF > /sys/kernel/debug/vgaswitcheroo/switch
Now after upgrading to 14.04, whenever my laptop is idle for sometime and goes to lock screen, it hangs. Same is case with suspend.
But if I lock it manually, then it doesn't hang.
The above problem happens only when graphic card is turned off.
Any suggestions, how to rectify this?
One possible solution that I think is to enable graphic card just before system locks or suspends. How to do this?