New Features Of The Linux 4.2 Kernel
Written by Michael Larabel in Software on 5 July 2015. Page 1 of 2. 5 Comments

If all goes according to plan, the Linux 4.2 kernel merge window will close this afternoon followed by the immediate release of the Linux 4.2-rc1 test version. With all major pull requests having already been submitted for Linux 4.2, here's an overview of the exciting new features and changed functionality to look forward to with this kernel version to officially debut later this summer!

With the Linux kernel rapidly getting bigger, Linux 4.2 is yet another exciting update. Below is a list of all the pull requests I've covered on Phoronix over the past two weeks of the changes that were of interest to me. Among the highlights for Linux 4.2 are the new AMDGPU kernel driver for supporting the very latest and future Radeon GPUs, Intel Broxton support, further support for various CPUs/architectures, support for the never-ending flow of new ARM development boards/platforms, F2FS file-system encryption support, NV-DIMM support, and other new Linux hardware support.

DRM / Graphics:

- The AMDGPU kernel DRM driver has finally been mainlined. This is the driver to support the Radeon R9 285 "Tonga" and all future GPUs, including Carrizo APUs and the to-be-supported Fiji/Fury GPUs. This AMDGPU driver will live alongside the current "Radeon" DRM driver as the kernel components to AMD's open-source Linux driver offering. In the future, the Catalyst Linux driver might also rely upon this new kernel driver so that the Catalyst binary blob would be isolated to user-space.


Open-source AMD R9 285 support is finally here!

- VCE1 video encode support was added to the Radeon DRM driver.

- The VirtIO GPU driver was the other new DRM component. This is for providing mode-setting the KVM/QEMU VirtIO guests and will be eventually be used as part of the Virgil3D project for exposing OpenGL/3D acceleration to guest VMs on Red Hat's virtualization stack.

- Initial support for Intel Broxton Atom SoCs should be initially enabled by Linux 4.2. Broxton features Skylake-class graphics while having a Goldmont-based CPU design. Broxton tablets/devices are expected to start appearing in the months ahead.


As usual there are many open-source GPU driver improvements with this next kernel, but sadly no Nouveau driver changes.

- Many other DRM core changes. The atomic mode-setting support should be stabilized, more drivers have taken advantage of the atomic interfaces, DisplayPort MST is better handled, the Adreno A306 is now supported by the MSM DRM driver, etc. Sadly, no major changes for the Nouveau (open-source NVIDIA driver) were integrated for Linux 4.2.

Processor / System Stuff:

- More x86 Assembly code was cleaned up that should now be easier to maintain and yield some performance improvements.

- New ARM boards and SoCs are supported by upstream. Among the new support is for the Freescale i.MX7D, ZTE ZX296702, and HiSilicon hi6220 with the new 96Boards HiKey board.

- The tracing subsystem pulled in many improvements for Intel processors.

- Jitter RNG was added in the crypto subsystem update.

- Write combining for x86 KVM and other mostly x86 focused improvements for the Kernel-based Virtual Machine.

- The mainline kernel code now supports the Renesas H8/300.

- Scheduler tweaks and improvements.

- Queue spinlocks are a new kernel feature.

- Support for ARCv2 and HS38 CPU cores.