While the Broadcom V3D driver has been part of the mainline kernel for supporting the graphics found on recent Raspberry Pi boards, currently it doesn’t support run-time power management. The lack of runtime PM has meant the GPU clock remains at full-speed even while idle.
Maíra Canal of Igalia posted a patch series today implementing run-time power management for the V3D DRM driver to benefit Raspberry Pi single board computers. Canal explained with the patch cover letter:
“This series introduces Runtime PM for Raspberry Pi’s GPU, V3D. Currently, the GPU clock stays up during the whole operation, even if the GPU is idle. By introducing Runtime PM, we can now turn off the clock completely during idle.”
Thus important for power efficiency and thermals to support GPU run-time power management just like other modern GPUs/drivers.
The patch series is now under review for the V3D driver. Due to the timing the earliest now this V3D run-time power management would be merged is the Linux v6.18 cycle later in the year.
