XPS 13 9380 opening lids intermittently wont wake from sleep

Read this for background information on Modern Standby.

Here's how I fixed that problem for my setup.

The default power plan for the XPS 13 9380 is the "Dell" power plan. That plan has hibernation enabled after 30 minutes. So, if you close the lid, after 30 minutes it will enter hibernation and require a power button press to turn on.

There are 2 ways to fix this. Choose whichever you prefer.

1. Change the power plan to "Balanced" instead of the Dell plan. Right click the battery/power icon, choose "power options", and change the plan to Balanced. The default Balanced plan has Hibernation disabled.

2. Modify the Dell power plan to increase or disable the Hibernation option. Right click the battery/power icon, choose "power options", look for the Dell plan and click the "change plan settings". Once in the plan settings look for the "Sleep" branch of the options tree. Under there there will be a Hibernate setting. By default it is set to 30 minutes on battery and 31 minutes plugged in. Increase those times or set it to "Never by using a value of 0.

After doing that my laptop now wakes immediately when I open the lid. I actually have mine set to hibernate after 120 minutes to save power, so I get the fast lid open wake for at least 2 hours after closing the lid, and need to hit the power button for anything longer.