Hi All im running centos 7 on my HP Probook 450. the problem im having is that when i put the Laptop to sleep (close the lid or press power button once) it goes to sleep fine. but to resume back, it cannot. it only lights up the keybord LED's to indicate PC is awake, but the screen will be blank. i have to force reboot ( long press of power button) for the laptop to come back up. what/were can i check to make sure it comes back from sleep nicely.