The Linux 6.17 kernel has merged a new driver for powering up the Imagination PowerVR-based graphics processor found within the Alibaba T-HEAD TH1520 RISC-V SoC. This power sequencing driver is just for being able to power-up the GPU before the actual graphics driver can takeover.

The T-HEAD TH1520 RISC-V SoC has seen [1]mainline Linux kernel support since 2023 but further work has been needed for the GPU support. The TH1520 as a reminder features four Xuantie C910 RISC-V cores while the graphics are Imagination BXM-4-64. Imagination's PowerVR open-source Direct Rendering Manager (DRM) driver has been [2]preparing for RISC-V support and the TH1520 SoC in particular but this power sequencing driver is merged for Linux 6.17 to just power on the graphics processor.

The TH1520's GPU requires a specific power-on sequence for properly initializing it and then as well when it comes time to powering it down. The sequence ensures the correct GPU clocks and having a proper hardware-required delay during the initialization process as well as during the power-off sequence.

This "pwrseq-thead-gpu" driver was merrged this week for the Linux 6.17 kernel. The Kconfig help text explains the new "POWER_SEQUENCING_TH1520_GPU" build option as:

"This driver handles the complex clock and reset sequence required to power on the Imagination BXM GPU on this platform."

Thanks to [3]merging this power sequencing driver, the T-HEAD's Imagination GPU is now close to working properly atop an open-source Linux graphics driver stack between the Imagination PowerVR DRM driver and the PVR Vulkan driver in Mesa.



[1] https://www.phoronix.com/news/Linux-6.5-SoCs

[2] https://www.phoronix.com/news/RISC-V-PowerVR-Driver-Support

[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ffec878fa5fba8c527cbbb006b0522ae0d6599ce