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# DSP, HDVICP2 and CORE (which put together HDVPSS, dual Cortex M3 and L3 bus) PM
The main difference between the two is that the Linux kernel itself knows pretty well how much the A8 is loaded at a given point in time (due to the fact that it's the kernel the one that schedule the kernel and userspace schedules its processes). Having a configurable CPU governor is a standard feature of Linux kernel, that can be found on PC/laptop tooPCs and laptops. Accordingly to user settings, the The Kernel changes A8 frequency/voltage on it's ownin accordance with user settings.
All the other stuff (DSP, HDVICP2 and CORE) are not managed directly from the kernel (e.g. dual M3 runs their own independent RTOS), for this reason it cannot choose which is the optimal working set from PM point of view. It's userspace application responsibility to choose the correct OPP ('''Operating Performance Points''') to reach a given result (e.g. Full-HD H264 encoding vs 720p H264 decoding).
