The talk is about U-Boot as a PSCI (Power State Coordination Interface) provider, which is a standard used on ARM systems to control power states of CPU cores and perform system operations like suspend, resume, reboot, and power off. The speaker explains the convenience, complexity, and security benefits of implementing PSCI in the firmware, and how it is used in virtualized setups. They also discuss the SMC (System Management Call) call convention used to implement PSCI and demonstrate how to implement PSCI functionality in U-Boot. The speaker concludes by showing an example of booting the Linux kernel using U-Boot as a PSCI provider.