Mesa 25.3-rc4 is available for testing as the latest weekly candidate as we work toward the Mesa 25.3 stable release this month.
Mesa 25.3-rc4 is out rather than going straight to Mesa 25.3.0 as there remain two outstanding blocker issues still being resolved. We’ll see if Mesa 25.3.0 in turn is released next week or if a -rc5 ends up being warranted.
Most notable with the Mesa 25.3-rc4 release is a fix for the Intel ANV open-source Vulkan driver to properly handle more Direct3D games running on Linux via Steam Play. Mesa 25.3-rc4 backports an Intel ANV driver change to ensure DIrect3D-compatible texturing for Proton (Steam Play). The patch by Intel engineer Alyssa Rosenzweig notes:
“Intel & AMD Direct3D drivers modify their rounding behaviour for texturing to match Direct3D expectations. Such behaviour is not conformant in Vulkan, and Intel hardware lacks a reasonable way to get NVIDIA’s behaviour (which uniquely works for Vulkan & Direct3D). The second best choice is to use Direct3D-compatible behaviour for Proton (via driconf) and our current Vulkan-conformant behaviour everywhere else. Given the APIs diverge and there is no Vulkan extension to control the behaviour explicitly, driconf’ing on the engineName is the reasonable solution.
anv already has a anv_force_filter_addr_rounding driconf option to force Direct3D behaviour for certain Direct3D titles. Here we simply apply it to all D3D10+ titles, aligning us with the Windows driver.
Note that D3D9 does not have this behaviour. We therefore use standard Vulkan behaviour for D3D9 to avoid breaking D3D9 titles, even though the engineName is the same as D3D10+.
This is the same solution radv uses, they call it radv_disable_trunc_coord. We could unify the driconf entries later.
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This fixes misrendering in piles of Direct3D games run on anv via Proton, including Assassin’s Creed Valhalla.”
Mesa 25.3-rc4 also brings fixes for the old Radeon R600g driver, a RADV driver workaround for Doom Dark Ages, a Vulkan runtime fix for calculating the stack size, a RADV workaround for No Man’s Sky, and various other fixes.
More details on the Mesa 25.3-rc4 fixes via the mailing list announcement.
