Mesa 19.3.0 Will Be Released Next Week
The GNU/Linux graphics driver stack Mesa released two new versions Wednesday: 19.2.7 and 19.3.0-rc6. The former is a bug-fix release for the stable Mesa branch and the latter is likely the last release-candidate for Mesa 19.3.0 which is filled with goodies such as new Vulkan extensions, Valve's Radeon ACO shader compiler, the faster Intel Iris graphics stack for Intel GPUs and more.
published 2019-12-06 - last edited 2019-12-13
GNU/Linux distributions leverage the Mesa graphics stack to render games like Transmissions: Element 120 (available for free in Valve's Steam store).
The short-log for the latest bug-fix for the Mesa 19.2 branch is indeed very short:
- radv: Allocate cmdbuffer space for buffer marker write.
- radv: Unify max_descriptor_set_size.
- gallium: Fix the ->set_damage_region() implementation
- intel/fs: Disable conditional discard optimization on Gen4 and Gen5
- anv: Set up SBE_SWIZ properly for gl_Viewport
- winsys/amdgpu: avoid double simple_mtx_unlock()
- i965: update Makefile.sources for perf changes
- radv: set writes_memory for global memory stores/atomics
- radv: fix enabling sample shading with SampleID/SamplePosition
- radv/gfx10: fix implementation of exclusive scans
- radv: fix compute pipeline keys when optimizations are disabled
- meson: Fix linkage of libgallium_nine with libgalliumvl
- Revert "draw: revert using correct order for prim decomposition."
radv are fixes for AMD graphics cards and i965 is a driver for all Intel iGPUs (not just the i965). There is nothing groundbreaking in Mesa 19.2.7, just the minor fixes listed above.
The changelog between Mesa 19.3.0-rc5 and 19.3.0-rc6 is equally short and it is mostly filled with tiny fixes:
- radv: Unify max_descriptor_set_size.
- radv: Fix timeline semaphore refcounting.
- gallium: Fix the ->set_damage_region() implementation
- panfrost: Make sure we reset the damage region of RTs at flush time
- etnaviv: remove dead code
- aco: don't split live-ranges of linear VGPRs
- aco: fix a couple of value numbering issues
- anv: Set up SBE_SWIZ properly for gl_Viewport
- winsys/amdgpu: avoid double simple_mtx_unlock()
- i965: update Makefile.sources for perf changes
- iris: Allow max dynamic pool size of 2GB for gen12
- driconf, glsl: Add a vs_position_always_invariant option
- drirc: Set vs_position_always_invariant for Shadow of Mordor on Intel
- aco: propagate p_wqm on an image_sample's coordinate p_create_vector
- aco: fix i2i64
- aco: add v_nop inbetween exec write and VMEM/DS/FLAT
- radv: set writes_memory for global memory stores/atomics
- nir/lower_io_to_vector: don't create arrays when not needed
- radv: fix enabling sample shading with SampleID/SamplePosition
- radv/gfx10: fix implementation of exclusive scans
Mesa's release-manager Dylan Baker had this to say in 19.3.0-rc6's release-announcement:
"Available today is mesa 19.3.0-rc6. Things are starting to slow down, and there are now only two open issues in the 19.3 milestone, so I'm hopeful that next week will bring 19.3.0 final, and not an rc7, but I can always be surprised.
By far radv + aco dominate the list of changes, but there's also changes to anv, panfrost, core gallium, fixes for OpenBSD, iris, and nir."
December 4th, 2019
Mesa 19.3.0 will have far more to offer than the short list of changes since 19.3.0-rc5 outlined above. It will debut a new ACO shader compiler for AMD GPUs developed by Valve as an alternative to the existing AMDGPU LLVM compiler. LLVM was made with entirely different things in mind. The ACO shader compiler is made specifically for shader compilation and it appears to be better at it. Do note that the ACO shader compiler is only available for the AMD Vulkan drivers (called "RADV"); it does not work with the "RadeonSI" driver Mesa driver AMD GPUs use for OpenGL.
Mesa 19.3.0 will also have quite a few new Vulkan extensions.
Intel was planning to make their shiny new Intel Iris driver for Intel iGPUs the default driver stack as of Mesa 19.3.0. These plans have been scrapped. The current i965 (actually for all Intel iGPUs) driver will remain Mesa's default until Mesa 20 is released in Q1 2020. Intel's Lisa Pearce cited Intel's desire to "ensure no destabilization for users" as the reason for the delay. Intel has some serious work to do with their i915 kernel driver (again, not just for i915, it is for all Intel iGPUs) if that is a goal. 5.3 series kernels prior to 5.3.14 are useless on Intel iGPUs and 5.4-series kernels are also utterly broken as of the latest 5.4.2 kernel release.
The source code for latest Mesa versions can be acquired from mesa.freedesktop.org/archive/.
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