Display Suspend Resume

Starting from Drive OS 7.0.3.0, Display supporst SC7. Display guest drivers use the Linux Power Management (PM) framework to suspend or resume the Guest OS. During this process, the DCE power-gates and unpower-gates the display hardware.

Suspend Flow

When the suspend callback is triggered through the Linux PM framework, the display driver running on the Guest VM saves its state, performs a null flip, and sends a deinit request to the DCE RM. During deinitialization, the DCE RM power-gates the display hardware. Once the Guest OS successfully completes its suspend sequence, the Power Manager sends a suspend request to the HVRTOS display driver. The HVRTOS driver saves its state and requests the DCE core to enter suspend. Finally, BPMP powers off the DCE.

Resume Flow

During resume, the BPMP firmware powers on the DCE. After the DCE is powered on, the Power Manager sends a resume request to the Display HVRTOS driver. Once the HVRTOS resume sequence completes, the DCE core resumes, followed by an init request to DCE RM from the Guest OS. During initialization, the DCE RM unpower-gates the display hardware.