Driver developer here. The sentences above are just plain wrong. Drivers have to implement callbacks for suspend. A driver needs to make sure it saves all of i

Driver developer here. The sentences above are just plain wrong. Drivers have to implement callbacks for suspend. A driver needs to make sure it saves all of its state before the suspend, and then it needs to make sure it restores all of its state after resume. S3 suspend often kills the state of every register that was previously written.