Precision 5550 / XPS 9500 very slow to resume from sleep, in linux.

Same issue with a Precision 5550 and an XPS 9500.

I wake from sleep and the screen turns on instantly, but nothing responds for at least five seconds.  It wouldn't be as bad if there were any indication of when I can start typing my password, but I have to just circle the touchpad until I see the pointer responding.  Occasionally I think it's ready and start typing but only get a partial password when I hit enter, which is the most annoying.

The same behavior exists on every linux I've tried, including the included Ubuntu 18.04

I don't see any BIOS settings that apply to sleep.  Any thoughts?