Hey, I just got my XPS 15 last week. I have an issue with brightness, I think its a driver issue or sensor something.
I use maximum performance / on power or balaced on battery. I love the 4K display is very bright.
Yet, sometimes it reduces brightness while I work. Could be a combination of keys, i didnt figure that yet.
After that, it wont let me enhance brightness at all. It looks as 80% and it wont go higher. After a while I found a solution - to disable HD Graphics 4600, and to enable again from Device Manager.
But, this is time consuming and annoying... Please help. I want to keep brightness higher.