Google's New Graphics Driver Developer Flips On UBWC For Freedreno

Rob Clark, the longtime leader of the Freedreno driver initiative providing open-source 3D graphics for Qualcomm Adreno hardware and who just recently jumped to Google to continue driver work, is using his new Chromium.org email address for flipping on UBWC in this driver.

UBWC is the Universal Bandwidth Compression feature of the Adreno hardware. Fritz Koenig of Google back in March contributed the initial code for this feature to reduce memory bandwidth via internal buffer compression. This helps in potential DDR memory power savings and also possible performance implications.

The initial UBWC code made it into Mesa 19.1 while now in Mesa 19.2-devel the UBWC feature is flipped on by default for Adreno 600 series hardware. The enablement also allows the FD_MESA_DEBUG environment variable to be used with the "noubwc" option to disable the functionality.

This default enabling came after patches before it addressed the remaining regressions around this bandwidth savings feature. Great to see Google's investments into this Adreno open-source driver stack.