Linux 4.8 Release - Main Changes, ARM & MIPS Architectures

Linus Torvalds has officially released Linux 4.8 last Sunday:

So the last week was really quiet, which maybe means that I could probably just have skipped rc8 after all. Oh well, no real harm done.

This obviously means that the merge window for 4.9 is open, and I appreciate the people who already sent in some pull requests early due to upcoming travel or other reasons. I’ll start pulling things tomorrow, and have even the most eager developers and testers hopefully test the final 4.8 release before the next development kernels start coming 😉

Anyway, there’s a few stragging fixes since rc8 listed below: it’s a mixture of arch fixes (arm, mips, sparc, x86), drivers (networking, nvdimm, gpu) and generic code (some core networking, with a few filesystem, cgroup and and vm things).

All of it pretty small, and there really aren’t that many of them. Go forth and test,
Linus

Linux 4.7 introduced support for AMD Radeon RX480 GPUs, parallel directory lookups, the new “schedutil” frequency governor with lower latency, EFI ‘Capsule’ firmware updates, and much more.

Some notable Linux 4.8 changes include:

HDMI-CEC framework
Kernel documentation system is now based on Sphinx
GPIO subsystem has a new user-space ABI for the management of general-purpose I/O lines; it is based on char devices and replaces the long-deprecated sysfs interface. You can check out tools/gpio/ directory with lsgpio, gpio-hammer, and gpio-event-mon for examples
Various file systems improvements for Btrfs, EXT-4 (unified encryption), OrangeFS (better in-kernel caching), Ceph (RADOS namespace support), XFS (Reverse-mapping support), etc…

Some improvements and new features specific to the ARM architecture and corresponding hardware platforms:

Allwinner:
- Allwinner A10/A20 – Display engine clocks (TCON, FE, DE), I2S audio interface (ASoC) driver, added NFC node to DTS
- Allwinner H3 – Clocks (through sunxi-ng), USB multi-reset lines support
- AXP2xx driver – External drivebus support, AXP223 USB power supply support, AXP809 PMIC support
- Broadcom BCM53125 support as it’s used in Lamobo / Banana Pi R1 router board.
- New boards – Polaroid MID2407PXE03 & inet86dz (Allwinner A23 tablets), Banana Pi M1+, Banana Pi M2+, Allwinner Parrot (Allwinner R16 EVB)

Rockchip:
- Many new peripherals added to RK3399 (eDP, clock controller, etc…)
- Preparations to use generic DMA mapping code in the Rockchip IOMMU driver
- Fixes for eMMC controller, SPI controller, eDP controller, and I2C
Amlogic
- AmLogic meson8b clock controller (rewritten)
- AmLogic gxbb clock controller
- Reset controller driver for Amlogic Meson
- New watchdog driver for Amlogic Meson GXBB (S905) SoC
- Added support for Amlogic Meson RNG in crypto drivers
- Some Amlogic ARM64 DTS updates
Samsung
- Enable drivers for Exynos7 and Exynos5433 based boards: S2MPS clock driver, SoC: RTC, SPI, watchdog, EHCI, OHCI, DWC3, ADC and PWM, Enable Samsung SoC sound
- Samsung ARM64 DTS Changes – Adjust the voltage of CPU buck regulator so scaling could work.
- Samsung DTS changes
  - Add missing async bridge for MFC power domain on Exynos5420. This fixes imprecise abort on s5p-mfc re-bind.
  - Define regulator supplies for MMC nodes on Exynos4412 Odroid boards and for TMU on Exynos542x Peach boards.
  - Thermal cleanups on Odroid XU3-family (Exynos5422).
  - Enable AX88760 USB hub on Origen board (Exynos4412)
  - Disable big.LITTLE switcher so the cpufreq-dt could be enabled.
  - Enable Samsung media platform drivers.
  - Enable some board-specific drivers for boards: Trats2, Universal C210.
  - Enable Virtual Video Test Driver on nulti_v7 and exynos defconfigs. Useful for testing
- Samsung drivers/soc updates:
  - Move the power domain driver from arm/mach-exynos and prepare for supporting ARMv8.
  - Add COMPILE_TEST.
  - Make SROMC driver explicitly non-module.
  - Endian-friendly fixes.
  - Fix size of allocation for Exynos SROM registers (too much was allocated)
- Add CEC interface driver present in the Samsung Exynos SoCs
- Added support for Exynos 5410 Odroid XU board
Qualcomm
- Added MDM9615 support
- Qualcomm ARM Based Driver Updates:
  - Rework of SCM driver
  - Add file patterns for Qualcomm Maintainers entry
  - Add worker for wcnss_ctrl signaling
  - Fixes for smp2p
  - Update smem_state properties to match documentation
  - Add SCM Peripheral Authentication service
  - Expose SCM PAS command 10 as a reset controller
  - Fix probe order issue in SCM
  - Add missing qcom_scm_is_available() API
- Qualcomm ARM64 Updates
  - Enable assorted peripherals on APQ8016 SBC
  - Update reserved memory on MSM8916
  - Add MSM8996 peripheral support
  - Add SCM firmware node on MSM8916
  - Add PMU node on MSM8916
  - Add PSCI cpuidle support on MSM8916
- Qualcomm Device Tree Changes:
  - Reverse BAM dma node reverts
  - Add BAM remote control options for affected platforms
  - Enable peripherals on APQ8074 dragonboard
  - Enable PMA8084 pwrky
  - Fix PMIC reg entries by removing unnecessary size element
  - Add SCM binding and support for all currently supported boards
  - Add Qualcomm WCNSS binding documentation
  - Rename db600c to SD_600eval and add peripheral nodes
  - Remove gpio key entry from Nexus7
  - Add APQ8060 based dragonboard and associated peripherals
  - Add ARMv7 PMU for IPQ4019
  - Update smem state cells to match documentation
- ARM64 defconfig: Enable PM8xxx pwrkey support, enable MSM8996 support
- ARM defconfig: Enable MSM9615 board support, enable MSM8660 pinctrl support
Mediatek
- Added Mediatek MT6755
- Display subsystem added to MT8173
- Support for Mediatek generation one IOMMU hardware
- New drivers for Mediatek MT6323 regulator
- new encoding codec driver for Mediatek SoC (linux-media): H.264/VP8/V4L2 video encoder drivers for MT8173
ARM64 – arm64 architecture has gained support for the kexec mechanism (allowing one kernel to boot directly into another) and kernel probes.
Other new ARM hardware or SoCs – NXP i.MX 7Solo, Broadcom BCM23550, Cirrus Logic EP7209 and EP7211 (clps711x platforms), Hisilicon HI3519, Renesas R8A7792, Apalis Tegra K1 board, LG LG1313, Renesas r8a7796, Broadcom BCM2837 (used in Raspberry Pi 3)

MIPS architecture changelog:

Fix memory regions reaching top of physical
MAAR: Fix address alignment
vDSO: Fix Malta EVA mapping to vDSO page structs
uprobes: fix incorrect uprobe brk handling, select HAVE_REGS_AND_STACK_ACCESS_API
Avoid a BUG warning during PR_SET_FP_MODE prctl
SMP: Fix possibility of deadlock when bringing CPUs online
R6: Remove compact branch policy Kconfig entries
Fix size calc when avoiding IPIs for small icache flushes
Fix pre-r6 emulation FPU initialisation
Fix delay slot emulation count in debugfs
CM: Fix mips_cm_max_vp_width for non-MT kernels on MT systems
CPS: Avoid BUG() when offlining pre-r6 CPUs
DEC: Avoid gas warnings due to suspicious instruction scheduling by manually expanding assembler macros.
FTLB: Fix configuration by moving configuration after probing, clear execution hazard after changing FTLB enable
Highmem: Fix detection of unsupported highmem with cache aliases
I6400: Don’t touch FTLBP chicken bits
microMIPS: Fix BUILD_ROLLBACK_PROLOGUE
Malta: Fix IOCU disable switch read for MIPS64
Octeon: Fix probing of devices attached to GPIO lines, fix kernel header to work for VDSO build, fix initialization of platform device probing.

You can find the full list of changes in Linux 4.8 changelog with comments only generated using git log v4.7..v4.8 --stat. A list of changes for Linux 4.8 will also soon be found on kernelnewbies.org.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.