Mesa 26.2-rc1 Released, Featuring Vulkan Extensions and Rusticl OpenCL 3.1 Support

The development of “Mesa,” the open-source 3D graphics stack, has branched off for its upcoming major version, Mesa 26.2, with the first release candidate, Mesa 26.2-rc1, now available. According to a report by Phoronix’s Michael Larabel on July 15, the stable release of Mesa 26.2 is slated for August. Until then, weekly release candidates will be made available.

Branch Strategy and Release Schedule

Mesa 26.2 was branched from the Mesa Git repository today, marking the start of development for Mesa 26.3-devel in the mainline. This transition signifies the end of this quarter’s feature development phase and the beginning of stabilization efforts. Weekly release candidates will be provided moving forward, with bug fixes and testing to continue until the stable release in August.

Mesa’s development cycle follows a roughly three-month schedule. Between the release of Mesa 26.2-rc1 and the stable version, the addition of new features will be frozen, with a focus on improving quality.

Major New Features and Improvements

The most significant changes in Mesa 26.2 include extensive support for Vulkan driver extensions and the completion of OpenCL 3.1 support in Rusticl.

Optimizations for Intel ANV and AMD RADV Drivers

Intel’s ANV (Vulkan driver) and AMD’s RADV (also Vulkan) have received numerous optimizations in this release. Notably, RADV now supports extensions such as VK_KHR_shader_fma, VK_KHR_device_fault, VK_EXT_shader_split_barrier (for GFX12), VK_KHR_performance_query (for GFX11), protectedMemory (for GFX10+ and VEGA10), among others. ANV has also added support for VK_GOOGLE_display_timing and other extensions.

The addition of protectedMemory support in RADV allows for graphics processing within protected memory regions, marking an important development for security-focused applications and games. The VK_KHR_device_fault extension improves error reporting for GPU hangs and device losses, enhancing debugging and failure response efficiency.

Rusticl Achieves OpenCL 3.1 Support

Rusticl, an OpenCL implementation written in Rust, now supports OpenCL 3.1 on Asahi, Iris, RadeonSI, LLVMpipe, and Zink drivers. OpenCL 3.1 builds upon OpenCL 3.0 with subgroup functionality extensions and compiler optimizations, contributing to improved compute workload performance.

One notable change is Rusticl’s requirement for a static C++ standard library. This workaround avoids conflicts with applications that use their own C++ standard libraries, enhancing compatibility with OpenCL applications. This is expected to improve usability for developers exploring OpenCL on Linux.

KosmicKrisp: Enabling Vulkan 1.4 on Apple Metal

KosmicKrisp, a layer translating Vulkan API to Apple’s Metal graphics API, has achieved Vulkan 1.4 support in this release. This development broadens the range of Vulkan applications that can run on Apple Silicon-equipped Macs. As Apple continues to focus on the Metal API, KosmicKrisp’s role as a bridge for Vulkan applications is becoming increasingly significant.

Maturation of NVIDIA’s NVK Vulkan Driver

NVIDIA’s open-source Vulkan driver, NVK, continues to expand its functionality. New extensions such as VK_NV_shader_atomic_float16_vector, VK_EXT_mesh_shader, and VK_KHR_shader_fma have been added. Once considered experimental, NVK is gradually becoming more practical as part of Mesa. However, its performance and stability compared to NVIDIA’s proprietary drivers remain to be fully evaluated.

KRAID Compiler:

Optimized for Arm Mali Panfrost/PanVK

The new KRAID compiler has been integrated into the Panfrost (OpenGL) and PanVK (Vulkan) drivers for Arm Mali GPUs. KRAID optimizes shader compilation for Mali GPUs, aiming to improve performance and reduce compile times.

Additionally, Panfrost and PanVK now support the G1-Ultra, G1-Premium, and G1-Pro GPUs, which belong to the latest generation of Arm Mali hardware. These advancements enhance graphics processing capabilities for embedded systems and mobile devices.

Ongoing Improvements in Vulkan Video

The development of Vulkan Video encoding/decoding capabilities continues in Mesa 26.2. Vulkan Video aims to provide hardware-accelerated video processing within the Vulkan API framework, and the Mesa team is steadily advancing this effort.

Maintenance of Legacy Drivers

Outdated Radeon R600g and R300g drivers have also received numerous fixes during the Mesa 26.2 feature development period. These drivers support older generations of AMD Radeon GPUs (such as the R600/R700/R800/R900 series). The continued maintenance of legacy hardware is good news for users relying on older GPUs in enterprise or embedded environments.

List of Newly Supported Vulkan Extensions

The release notes for Mesa 26.2 enumerate numerous new Vulkan extensions. Key updates by driver include:

RADV (AMD): VK_KHR_shader_fma, VK_KHR_device_fault, VK_EXT_shader_split_barrier (GFX12), VK_KHR_performance_query (GFX11), VK_EXT_pipeline_protected_access, VK_KHR_maintenance11 (replacing VK_KHR_maintenance5), VK_KHR_shader_abort, VK_EXT_shader_atomic_float, and protectedMemory (GFX10+/VEGA10).

ANV (Intel): VK_GOOGLE_display_timing (including KHR_display support, opt-in for X11/Wayland), VK_EXT_present_timing (WSI/X11).

NVK (NVIDIA): VK_NV_shader_atomic_float16_vector, VK_EXT_mesh_shader, VK_KHR_shader_fma, VK_EXT_shader_atomic_float.

PanVK (Arm Mali): VK_EXT_shader_uniform_buffer_unsized_array, VK_EXT_dynamic_rendering_unused_attachments, VK_EXT_conservative_rasterization, VK_EXT_extended_dynamic_state3, VK_KHR_shader_fma, VK_KHR_compute_shader_derivatives, VK_ARM_rasterization_order_attachment_access, VK_EXT_rasterization_order_attachment_access.

PVR (PowerVR): VK_KHR_present_id, VK_KHR_present_wait, VK_KHR_workgroup_memory_explicit_layout, VK_EXT_subgroup_size_control, VK_EXT_shader_subgroup_ballot, VK_EXT_shader_subgroup_vote, VK_EXT_index_type_uint8.

HASVK (Intel Haswell): VK_KHR_calibrated_timestamps, VK_KHR_present_id2, VK_KHR_present_wait2, VK_EXT_present_timing.

V3DV (Broadcom VideoCore): Includes VK_GOOGLE_display_timing support.

These extensions are critical updates for game engine and professional application developers, enabling better hardware functionality through the Vulkan API.

Detailed Insights into Rusticl’s OpenCL

3.1 Support

Rusticl, Mesa’s OpenCL implementation written in Rust, is gaining traction for GPU compute applications. In Mesa 26.2, OpenCL 3.1 is supported on five drivers: Asahi, Iris, RadeonSI, LLVMpipe, and Zink.

OpenCL 3.1’s key feature is the enhancement of subgroup functionality. Specifically, the cl_khr_subgroup_rotate extension has been added to the RadeonSI and Iris drivers, enabling efficient data rotation operations within subgroups. This is particularly effective for workloads requiring data shuffling, such as image processing and cryptographic algorithms.

The strengthened dependency on a static C++ standard library addresses compatibility issues with applications bundling custom C++ runtimes. This change ensures that Rusticl’s OpenCL implementation functions correctly in such environments.

GL_ARB_texture_query_lod and Panfrost

The Panfrost driver (v9 and onwards) now supports the GL_ARB_texture_query_lod extension, which allows shaders to query the mipmap level of a texture. This is useful for dynamically balancing quality and performance in texture-level-of-detail-dependent shader processing. It is available for Mali GPUs of the G9x generation and later.

Initial Work on GFX12.1 Support

Initial development for supporting AMD’s next-generation GPU architecture, GFX12.1, was merged during Mesa 26.2’s development phase. GFX12.1 is speculated to correspond to AMD’s RDNA 5 generation or its derivatives. While still in its early stages, full support may be achieved in future Mesa releases.

Significance of VK_GOOGLE_display_timing

The VK_GOOGLE_display_timing extension provides a mechanism for Vulkan applications to control display timing. In Mesa 26.2, this extension has been enabled for KHR_display (displays using DRM kernel mode setting) and is opt-in for X11 and Wayland environments. Supported by drivers including ANV, HASVK, HK, NVK, PanVK, PVR, RADV, TU (Turnip: Vulkan driver for Qualcomm Adreno GPUs), and V3DV, this extension is particularly useful for low-latency displays or tear-free rendering in VR/AR applications and games.

Stabilization and Release Candidate Process

It typically takes 4–6 weeks from Mesa 26.2-rc1 to the final stable release. During this time, the community conducts testing and submits bug reports, with critical issues addressed. Weekly release candidates are provided, and the final release occurs once a candidate is deemed sufficiently stable.

For developers, most new features are available as of Mesa 26.2-rc1, allowing for early testing and preparation for migration.

Editorial Opinion

In the short term, the release of Mesa 26.2-rc1 has a direct impact on the Vulkan ecosystem on Linux. Optimizations in RADV and ANV improve the performance of Windows games via Steam Play (Proton), enhancing the Linux gaming experience. The addition of protectedMemory and VK_KHR_device_fault offers practical benefits for developers in terms of debugging and stability. Rusticl’s support for OpenCL 3.1 broadens options for GPU compute applications such as machine learning inference and scientific computations.

From a long-term perspective, the integration of the KRAID compiler and early support for GFX12.1 signal Mesa’s strengthening position as a platform for both Arm and AMD architectures. Enhanced functionality in the NVK driver could make NVIDIA GPUs more practical with open-source drivers, reducing reliance on proprietary alternatives. The ongoing development of Vulkan Video represents a significant step toward establishing a standard API for video decoding/encoding.

References

• “Mesa 26.2-rc1 Released In Ending Feature Work For This Quarter’s 3D Graphics Stack”, by Michael Larabel — Phoronix, 2026-07-15T21:10:31.000Z (ARR)
• Source URL: https://www.phoronix.com/news/Mesa-26.2-rc1-Released