Open-Source Radeon Vulkan Driver Lands APU Fix For Red Dead Redemption 2

For those with an AMD APU system like the Steam Deck and using the Mesa Radeon Vulkan driver "RADV" and wanting to enjoy the popular game Red Dead Redemption 2, an important fix has been merged for Mesa 22.3.

In addressing "memory explosion" issues with Red Dead Redemption 2 when running on AMD APUs under Linux with Steam Play, the Mesa RADV driver has added a new game-specific option and enabled it for the RDR2 game.

The new "radv_enable_unified_heap_on_apu" option forces the driver to expose only one memory heap of vRAM due to "some games seem to perform better" when only one heap of vRAM is exposed for APUs. Discrete GPU behavior is unchanged.

The second patch as part of this merge request then uses the DriConf infrastructure to enable this option when running the game Red Dead Redemption 2 based on the process name.

The patches by Valve open-source driver developer Samuel Pitoiset explained, "This seems to resolve the memory explosion without hurting performance. This workaround is only applied for native Vulkan."

Due to the whitelisting, these two patches shouldn't affect RADV for other games while with time we'll see if any other games on AMD APUs end up needing a similar workaround with this "radv_enable_unified_heap_on_apu" option.