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Linux 4.20 was released on Sun, 23 Dec 2018.

Summary: This release includes support for a new way to measure the system load; it adds support for future AMD Radeon Picasso and Raven2 and enables non-experimental support for Radeon Vega20; it adds support for the C-SKY CPU architecture and the x86 Hygon Dhyana CPUs; a TLB microoptimization brings a small performance win in some workloads; TCP has switched to a "Early Departure Time" model; a mechanism to turn memfd regions into dma-buf allows qemu to improve virtualized graphics performance; it also includes the latest round of fixes for CPU security bugs; and it also adds many new drivers and other improvements.

Contents

Prominent features
Core (various)
File systems
Memory management
Block layer
Tracing, perf and BPF
Virtualization
Cryptography
Security
Networking
Architectures
Drivers
List of merges
Other news sites

1. Prominent features

1.1. Pressure stall information for better overview of system load

When systems are overcommitted and resources become contended, it's hard to tell exactly the impact this has on workload productivity, or how close the system is to lockups and OOM kills. In particular, when machines work multiple jobs concurrently, the impact of overcommit in terms of latency and throughput on the individual job can be enormous. In order to maximize hardware utilization without sacrificing individual job health or risk complete machine lockups, this release adds pressure stall information, a way to quantify resource pressure in the system.

Under /proc/pressure/ (and also inside each cgroup), several files expose the percentage of time the system is stalled on CPU, memory, or IO, respectively. These percentages of walltime can be thought of as pressure percentages, and they give a general sense of system health and productivity loss incurred by resource overcommit. They can also indicate when the system is approaching lockup scenarios and OOMs.

Documentation: Documentation/accounting/psi.txt

Recommended LWN article: Tracking pressure-stall information

1.2. AMD Radeon Picasso + Raven2 support, and Vega20 enablement

This release adds support for Raven2 APU and Picasso APUs. Also, support for Vega20 is no longer considered experimental.

1.3. More efficient virtualized graphics

This release includes udmabuf, a device that can turn memfd regions into dma-buf. It allows qemu to create dmabufs for the vga framebuffer or virtio-gpu resources. Then they can be passed around to display those guest things on the host. To spice client for classic full framebuffer display, and hopefully some day to wayland server for seamless guest window display.

1.4. New chinese CPUs: C-SKY architecture and Hygon Dhyana x86 CPUs

This release adds support for new architecture: C-SKY architecture, a 32 bit chinese CPU ISA

There is also support for Hygon Dhyana Family 18h, a new x86 processor coming from the AMD–Chinese joint venture

1.5. TCP: switch to Early Departure Time model

Internet grew following a AFAP ("As Fast As Possible") idea. Due to the constraints of modern hardware, this model is not optimal any more. This release switches the TCP stack to Early Departure Time model

See:

1.6. Make lazy TLB even lazier

As TLB flushes are extremely expensive, a technique called lazy TLB is employed by Linux which avoids unnecessary TLB flushes by processes which do not access the userspace page tables as the kernel portion of the address space is always visible. This release tries to use lazy TLB used even lazier: On most workloads, the number of context switches far exceeds the number of TLB flushes sent. Optimizing the context switches, by always using lazy TLB mode, speeds up those workloads. This reduces total CPU use in the system by about 1-2% for a memcache workload on two socket systems, and by about 1% for a heavily multi-process netperf between two systems.

1.7. Another round of fixes for CPU security bugs

x86: Remedy the overhead of STIBP/IBPB with per task indirect branch speculation control
x86: Harden spectre v2 userspace-userspace protection
x86: The "minimal retpoline" support is no longer useful and has been removed
arm64: Support for the new ARMv8.5 PSTATE.SSBS bit which can be used to mitigate Spectre-v4 dynamically without trapping to EL3 firmware

2. Core (various)

fanotify super block marks: It implement the new mark type FAN_MARK_FILESYSTEM to enable monitoring of filesystem events on all filesystem objects regardless of the mount where event was generated commit, commit, commit
New fanotify event info API: In order to identify which thread triggered the event in a multi-threaded program, add the FAN_REPORT_TID flag in fanotify_init to opt-in for reporting the event creator's thread id information commit, commit, commit, commit, commit, commit, commit
(FEATURED) psi: pressure stall information for CPU, memory, and IO commit, commit, commit, commit, commit, commit, commit, commit, commit
init: add root=PARTLABEL=<name> support commit
task scheduler
- Migrate 'misfit' tasks on asymmetric capacity systems (e.g. Arm big.LITTLE) commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
- Set SD_ASYM_CPUCAPACITY flag automatically commit, commit, commit, commit
Android binder: Add BINDER_GET_NODE_INFO_FOR_REF ioctl. It allows the context manager to retrieve information about nodes that it holds a reference to, such as the current number of references to those nodes commit
gcc-plugins: Add the STACKLEAK plugin, which erases the kernel stack before returning from syscalls. That reduces the information which kernel stack leak bugs can reveal and blocks some uninitialized stack variable attacks commit, commit, commit
Allow dedupe of user owned read-only files commit, commit
qspinlock_stat: Count instances of nested lock slowpaths commit
Building
- Remove oldnoconfig and silentoldconfig targets commit, commit
- Add the following GCC flags unconditionally: -Wvla, -Wdeclaration-after-statement, -Wno-pointer-sign, -Wno-unused-but-set-variable commit, commit, commit, commit

3. File systems

XFS
- Support returning partial reflink results. For example, if userspace sends a 1GB clone request and we run out of space halfway through, we at least can tell userspace that we completed 512M of that request like a regular write commit
BTRFS
- qgroups: Reduce dirty extents for metadata. It significantly improves balancing with quota enabled commit, commit, commit, commit, commit, commit
- Improve btrfs btree locking modes. It significantly improves performance: more files/sec in fsmark, better perf on multi-threaded workloads (filebench, dbench), fewer context switches, better latency, etc commit
CIFS
- Compounding support, it aggregates several operations to avoid round trips commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
- Implement direct I/O: The file system passes the I/O data directly from user-space buffer to the transport layer, when file system is mounted with cache-none commit, commit, commit
- Add ioctl for QUERY_INFO passthrough to userspace. It allows userspace tools to query the raw info levels for cifs files and process the response in userspace commit
- Add support for ioctl on directories commit
- Show number of current open files in /proc/fs/cifs/Stats commit
F2FS
- Support superblock checksum commit
- Checkpoint disabling commit
- Account meta IO and skip count of background GC in status debugfs entry commit, commit
- Add new idle interval timing for discard and gc paths commit
FUSE
- Allow caching readdir commit, commit, commit, commit, commit, commit, commit, commit, commit
- Add support for copy_file_range() commit
- Enable caching of symlinks commit
GFS2
- Add support for ioctl getfslabel commit
NFSD
- Server side support for async COPY commit, commit, commit, commit
9P
- Add mount option for lock retry interval commit
AFS
- Add support for the YFS variant of the AFS server commit, commit, commit
- Allow dumping of server cursor on operation failure commit
CEPH
- Add support for copy_file_range commit, commit, commit, commit
OCFS2
- Support partial clone range and dedupe range commit
OVERLAYFS
- Automatically enable redirect_dir on metacopy=on commit

4. Memory management

XArray (recommended LWN article The XArray data structure) commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
Introduce kmalloc-reclaimable caches which can be reclaimed under memory pressure (typically through a shrinker), these are shown as "kmalloc-rcl-SIZE" in /proc/slabinfo. This makes the slab pages accounted as NR_SLAB_RECLAIMABLE in vmstat, which is reflected also the MemAvailable counter in /proc/meminfo and in overcommit decisions. A new KReclaimable counter is added to that file show the sum of all reclaimable kernel allocations, including slab. The NR_INDIRECTLY_RECLAIMABLE_BYTES counter is repurposed commit, commit, commit, commit, commit, commit
zero-seek shrinkers: implement a "zero-seek" setting for shrinkers that results in a target ratio of 0:1 between their objects and IO-backed caches. This allows such virtual caches to grow when memory is available (they do cache/avoid CPU work after all), but effectively disables them as soon as IO-backed objects are under pressure commit
workingset: add vmstat counter for shadow nodes commit
kmemleak: add module param to print warnings to dmesg commit
contiguous page allocator: Improve large page preservation handling commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
brk and mremap: downgrade mmap_sem to read when shrinking commit, commit
userfaultfd: allow get_mempolicy(MPOL_F_NODE|MPOL_F_ADDR) to trigger userfaults commit
zap pages with read mmap_sem in munmap for large mapping, to improve mmap_sem scalability commit, commit, commit
Address issues slowing persistent memory initialization commit, commit, commit
Remove CONFIG_HAVE_MEMBLOCK commit and CONFIG_NO_BOOTMEM commit, commit
slub: Extend the slub_debug syntax to handle multiple slabs commit
lz4: update LZ4 decompressor module commit

5. Block layer

Convert a bunch of drivers from the old legacy IO interface to blk-mq commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
blk-mq: Enable support for runtime power management commit
Introduce BLKGETNRZONES ioctl: Get a zoned block device total number of zones commit
Introduce BLKGETZONESZ ioctl: Get a zoned block device zone size commit
md: raid10: support add disk under grow mode commit
Expose through sysfs the nr_zones field of struct request_queue commit
kyber: implement improved heuristics commit
nvmem: add support for cell info commit and cell lookups commit
Remove DAC960 driver commit

6. Tracing, perf and BPF

perf trace: Introduce perf trace --max-events for stopping 'perf trace' when that many syscalls (enter+exit), tracepoints or other events such as page faults take place. Support that as well on a per-event basis, e.g.: perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/ Will stop when 2 context switches, 4 block plugs, 1 block unplug and 3 net_dev_queue tracepoints take place commit, commit, commit, commit
uprobes: Support SDT markers having reference count (semaphore) commit, commit, commit, commit
uprobe: support reference counter in fd-based uprobe commit
Make perf script easier to use for itrace. Implement a range of improvements to make it easier to look at itrace traces with perf script commit, commit, commit, commit, commit
perf script: Allow extended console debug output commit
perf scripts python: exported-sql-viewer.py: Add All branches report commit, add ability to display all the database tables commit, add ability to find symbols in the call-graph commit, add ability to shrink / enlarge font commit, add support for multiple sub-windows commit
kprobes: Allow kprobe-events to record module symbol commit
probeevent: Improve fetcharg features commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
BPF
- Implement queue/stack maps. This patchset implements two new kind of eBPF maps: queue and stack. Those maps provide to eBPF programs the peek, push and pop operations, and for userspace applications a new bpf_map_lookup_and_delete_elem() is added commit, commit, commit, commit, commit, commit
- Add socket lookup support commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
- Adding supprot for two new bpf's tcp sockopts: TCP_SAVE_SYN (set) and TCP_SAVED_SYN (get) commit
- bpftool support for sockmap use cases commit, commit
- per-cpu cgroup local storage. It implements per-cpu cgroup local storage and provides an example how per-cpu and shared cgroup local storage can be used for efficient accounting of network traffic commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
- bpftool: add support for BPF_MAP_TYPE_REUSEPORT_SOCKARRAY maps commit
- bpftool: add net support. The functionality to dump network driver and tc related bpf programs are added commit, commit, commit
bpftool: add map create command commit

7. Virtualization

vfio: add vgpu edid support commit, commit
virtio-balloon: support free page reporting commit, commit, commit
Add support for overriding the default driver for a VMBus device in the same way that it can be done for PCI devices commit

8. Cryptography

Implement a generic crypto statistics commit and add cryptostat userspace commit
KEYS
- Support TPM-wrapped key and crypto ops. This adds 1) keyctl() functions that permit an asymmetric-type key to be used to encrypt, decrypt, sign and verify a small piece of data using the public and/or private key held in the kernel 2) an asymmetric-key parser for PKCS#8 to allow RSA private keys to be passed to the kernel 3) an asymmetric-key parser for TPM-wrapped key blobs commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
ofb: add output feedback mode commit
speck: remove Speck commit
crc-t10dif: Allow current transform to be inspected in sysfs commit

9. Security

LSM: Provide init debugging infrastructure with lsm.debug kernel boot parameter commit
apparmor: Allow packet filtering based on secmark policy commit, commit
tpm: add support for nonblocking operation commit

10. Networking

(FEATURED) TCP: switch TCP and and fair-queue scheduler to Early Departure Time model. See: Evolving from AFAP: Teaching NICs about time commit, commit, commit, commit, commit, commit, commit, commit, commit
Implement kernel filtering of route dumps by protocol (e.g., which routing daemon installed the route), route type (e.g., unicast), table id and nexthop device. iproute2 has been doing this filtering in userspace for years; pushing the filters to the kernel side improves efficiency on large scale systems commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
TCP: Previously TCP initial receive buffer is ~87KB by default and the initial receive window is ~29KB (20 MSS). This patch changes the two numbers to 128KB and ~64KB (rounding down to the multiples of MSS) respectively commit
batman-adv: Enable LockLess TX for softif commit
bridge: add support for per-port vlan stats commit
Wireless
- Add support for 60GHz band channels 5 and 6 commit
- Allow userspace to enable FTM responder functionality with the addition of new Netlink flag attribute NL80211_ATTR_FTM_RESPONDER with configurable lci/civic ocation parameters commit, commit
- VHT extended NSS support commit, commit, commit, commit
- Add per peer statistics to compute FCS error rate commit
- Add he_capa debugfs entry commit
packet scheduler
- Add hardware specific counters to TC actions commit, commit
- Add sockopt PACKET_IGNORE_OUTGOING to ignore outgoing packets. Note that the *BSDs already have something similar: BIOCSSEESENT/BIOCSDIRECTION and BIOCSDIRFILT commit
- Add support for configuring the taprio scheduler commit
DNS: Allow the dns resolver to retrieve a server set commit
Distributed Switch Architecture
- Add Lantiq / Intel GSWIP tag support commit
- Expose tagging protocol to user-space commit
Introduce eBPF flow dissector, a more secure flow dissector. Recommended LWN article: Writing network flow dissectors in BPF. commit, commit, commit, commit
geneve: add ttl inherit support commit
rtnetlink: add IFA_TARGET_NETNSID for RTM_GETADDR. The goal is to make it possible to perform RTM_GETADDR requests on different network namespaces commit, commit, commit, commit, commit, commit, commit, commit, commit
Add support for dumping addresses for a specific device commit, commit, commit, commit
IPv6
- Add a sysctl (skip_notify_on_dev_down) to skip DELROUTE message on device down, to mimic IPv4 behaviour commit
- Add sockopt IPV6_MULTICAST_ALL analogue to IP_MULTICAST_ALL commit
- Allow the l3mdev to be a loopback commit
ncsi
- Add NCSI OEM command support commit and Broadcom OEM command commit
- Extend NC-SI Netlink interface to allow user space to send NC-SI command commit
neighbour
- Allow setting of NTF_ROUTER by an external entity (eg BGP E-VPN control plane) commit
- Send netlink notification if NTF_ROUTER changes commit
netfilter
- nf_tables: add SECMARK support commit
- nf_tables: add xfrm expression commit
- nft_osf: Add ttl option support commit
- xt_IDLETIMER: add sysfs filename checking routine commit
netlink
- Add new socket option to enable strict checking on dumps commit
- Add NLA_REJECT policy type which does nothing but reject (with EINVAL) validation of any messages containing this attribute commit
- Add ethernet address policy type which checks for exact size, and rejects the attribute if the length isn't ETH_ALEN commit
netpoll: Enable netconsole IPv6 link local address commit
rxrpc: Add /proc/net/rxrpc/peers to display peer list commit
vhost_net XDP TX batching: try to batch submitting packets to underlayer socket through msg_control during sendmsg() commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
vhost: improve performance when enable busyloop commit, commit, commit
tipc: support binding to specific ip address when activating UDP bearer commit
TLS
- Add support for async encryption of records for performance commit
- sockmap integration for ktls. It allows for introspection or filtering of L7 data with the help of BPF programs operating on a common input context commit, commit, commit, commit, commit, commit, commit, commit
veth
- XDP stats improvement commit, commit, commit
- Add software timestamping commit
virtio_net: ethtool tx napi configuration commit

11. Architectures

ARM
- device tree sources
  - Two boards get added for TI OMAP: Moxa UC-2101 is an industrial computer commit, commit; GTA04A5 is a minor variation of the motherboards of the GTA04 phone commit
  - Clearfog is a nice little board for quad-core Marvell Armada 8040 network processor commit
  - Two additional server boards come with the Aspeed baseboard management controllers: Stardragon4800 commit is an arm64 reference platform made by HXT (based on Qualcomm's server chips), and TiogaPass commit, commit is an Open Compute mainboard with x86 CPUs. Both use the ARM11 based AST2500 chips in the BMC
  - NXP i.MX usually sees a lot of new boards each release. This time there we only add one minor variant: ConnectCore 6UL SBC Pro commit uses the same SoM design as the ConnectCore 6UL SBC Express added later. However, there is a new chip, the i.MX6ULZ, which is an even smaller variant of the i.MX6ULL, with features removed. There is also support for the reference board design, the i.MX6ULZ 14x14 EVK commit, commit
  - A new Raspberry Pi variant gets added, this one is the CM3 compute module based on bcm2837, it was launched in early 2017 but only now added to the kernel, both as 32-bit and as 64-bit files, as we tend to do for Raspberry Pi commit
  - On the Allwinner side, everything is again about cheap development boards, usually of the "Fruit Pi" variety. The new ones this time are: Orange Pi Zero Plus2 commit, Orange Pi One Plus commit, Pine64 LTS commit, Banana Pi M2+ H5 commit, commit. The last one of these is now a 64-bit version of the earlier Banana Pi M2+ H3, with the same board layout.
  - For Rockchips, we get another variant of the 32-bit Asus Tinker board, the model 'S' based on rk3288 commit, and three now boards based on the popular RK3399 chip: ROC-RK3399-PC commit, Rock960 commit, RockPro64 commit. These are all quite powerful boards with lots of RAM and I/O, and the RK3399 is the same chip used in several Chromebooks. Finally, we get support for the PX30 (aka rk3326) chip, which is based on the low-end 64-bit Cortex-A35 CPU core. So far, only the evaluation board is supported commit, commit
  - One more Banana Pi is added with a Mediatek chip: Banana Pi R64 is based on the MT7622 WiFi router platform, and the first product the arm maintainer has seen with a 64-bit Mediatek chip in that market commit
  - For HiSilicon, we gain support for the Hi3670 SoC commit and HiKey 370 development board commit, which are similar to the Hi3660 and Hikey 360 respectively, but add support for an NPU
  - Amlogic gets initial support for the Meson-G12A chip (S905D2) commit, another quad-core Cortex-A53 SoC, and its evaluation platform. On the 32-bit side, we gain support for an actual end-user product, the Endless Computers Endless Mini based on Meson8b (S805) commit
  - Qualcomm adds support for their MSM8998 SoC and evaluation platform. This chip is commonly known as the Snapdragon 835, and is used in high-end phones as well as low-end laptops commit
  - For Renesas, a very bare support for the r8a774a1 (RZ/G2M) is added commit, commit, commit, commit but no boards for this one. However, we do add boards for the previously added r8a77965 (R-Car M3-N): the M3NULCB Kingfisher commit and the M3NULCB Starter Kit Pro commit
  - While we have lots of DT changes for NVIDIA to update the existing files, the only board that gets added is the Toradex Colibri T20 on Colibri Evaluation Board for the old Tegra2 commit
  - Synaptics add support for their AS370 SoC, which is part of the (formerly Marvell) Berlin line of set-top-box chips used e.g. in the various Google Chromecast. Only the .dtsi gets added at this point, no actual machines commit
  - mvebu: Add device tree for db-88f6820-amc board commit
  - shmobile: Add basic RZ/A2 SoC support commit
  - shmobile: r8a7744: Basic SoC support commit
  - u300: Delete dummy SPI chip commit
  - imx6qdl: Add Engicam i.Core 1.5 MX6 commit
- amlogic: add meson-canvas driver commit
- coresight: Add support for CLAIM tag protocol commit
- coresight: etm-perf: Add support for ETR backend commit
- crypto: ghash-ce: implement support for 4-way aggregation commit
- KVM: Enable 32 bits kvm vcpu events support commit
- ARM64
  - (FEATURED) Support for Common Not Private (CnP) translations allowing threads of the same CPU to share the TLB entries commit, commit
  - Support for the new ARMv8.5 PSTATE.SSBS bit which can be used to mitigate Spectre-v4 dynamically without trapping to EL3 firmware commit, commit, commit, commit, commit, commit, commit
  - Add accelerated crc32 routines commit
  - crypto: aes-blk: add support for CTS-CBC mode commit
  - kvm: Allow tuning the physical address size for VM commit
X86
- (FEATURED) Add x86 architecture support for a new processor: Hygon Dhyana Family 18h commit
- (FEATURED) Make lazy TLB mode even lazier: On most workloads, the number of context switches far exceeds the number of TLB flushes sent. Optimizing the context switches, by always using lazy TLB mode, speeds up those workloads. This results in about a 1% reduction in CPU use on a two socket Broadwell system running a memcache like workload commit, commit, commit, commit, commit, commit, commit
- (FEATURED) Remedy the STIBP/IBPB overhead commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
- qspinlock: Improve determinism for x86 commit, commit, commit, commit
- (FEATURED) Harden spectrev2 userspace-userspace protection commit, commit, commit
- Remove minimal retpoline support commit
- EDAC
  - altera: Add Stratix10 peripheral support commit
  - amd64: Add Family 17h, models 10h-2fh support commit
  - amd64: Add Hygon Dhyana support commit
- crypto: remove SHA multibuffer routines and mcryptd commit
- perf
  - intel/uncore: Add more IMC PCI IDs for KabyLake and CoffeeLake CPUs commit
  - intel/uncore: Support CoffeeLake 8th CBOX commit
  - intel: Add a separate Arch Perfmon v4 PMI handler commit
- platform
  - Add Intel AtomISP2 dummy / power-management driver commit
  - Add LG Gram laptop special features driver commit
- stm class: Add support for MIPI SyS-T protocol commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
- hyper-v
  - Allow PV qspinlock work on Hyper-V commit, commit
  - PV IPI support for Windows guests commit, commit, commit, commit, commit, commit, commit
- KVM
  - nVMX: initial implementation of Enlightened VMCS for nested Hyper-V on KVM. Using it helps to spare 1500 cpu cycles for nested vmexit (tight cpuid loop in WS2016 with Hyper-V role on KVM: 15200 cycles -> 13700 cycles) commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
  - Add coalesced pio support commit
  - Add a new per-VM capability (KVM_CAP_EXCEPTION_PAYLOAD) will be introduced. When this capability is enabled by userspace, the faulting linear address will be included with the information about a pending #PF in L2, and the "new DR6 bits" will be included with the information about a pending #DB in L2. This ancillary exception information is carried in a new "payload" field commit, commit, commit, commit, commit, commit, commit
  - VMX: enable nested virtualization by default commit
CSKY
- (FEATURED) New architecture, C-SKY commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
PARISC
- Added alternative infrastructre commit
- Include compressed vmlinux file in vmlinuz boot kernel commit
- Remove the dead ccio-rm-dma driver commit
POWERPC
- Maintain a cache of SLB entries for each process and preload them on context switch. Leading to a 27% speedup for our context switch benchmark on Power9 commit, commit
- Add stack protector support for 32 and 64-bit, with a per-task canary commit, commit
- Add support for physical memory up to 2PB in the linear mapping on 64-bit Book3S. We only support up to 512TB as regular system memory, otherwise the percpu allocator runs out of vmalloc space commit
- Enable THP migration on 64-bit Book3S machines (eg. Power7/8/9) commit
- Add support for PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP commit
- Add support for function error injection commit
- pseries: Add driver for PAPR SCM regions commit
- pseries: PAPR persistent memory support commit
- KVM
  - Nested HV KVM support for radix guests on POWER9. The performance is much better than with PR KVM. Migration and arbitrary level of nesting is supported commit, commit, commit
  - Add a debugfs file to dump radix mappings commit
RISC-V
- Add futex support commit
- Allow to disable FPU support commit
- Show CPU ID and Hart ID separately in /proc/cpuinfo commit
- Add FP register ptrace support for gdb commit
S390
- Extend the pkey API to provide random protected keys, this is useful for encrypted swap device with ephemeral protected keys commit, commit, commit, commit, commit
- Add KASAN support commit, commit, commit
- Add support for virtually mapped kernel stacks commit
- zcrypt: Improved access control for the zcrypt driver, multiple device nodes can now be created with different access control lists commit, commit
- vfio-ap: Introduce a new AP device driver. This driver grants access to Adjunct Processor (AP) devices via the VFIO mediated device interface commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
- qeth
  - Add TSO support for L2 devices commit
  - Add support for IPv6 TSO commit
  - Report 25Gbit link speed commit
  - speed up TSO transmission commit
- KVM: s390: interface to clear CRYCB masks commit
MIPS
- mscc: add DT for Ocelot PCB120 commit
SPARC
- Add support for perf annotate commit
- Add support for perf jitdump commit

12. Drivers

12.1. Graphics

(FEATURED) udmabuf device to turn memfd regions into dma-buf commit
Add per-plane pixel blend mode property commit
amdgpu
- Merge amdkfd and amdgpu into one module commit
- Add DisplayPort CEC-Tunneling-over-AUX support commit
- (FEATURED) Picasso APU support + VCN dynamic powergating commit, commit
- (FEATURED) Raven2 APU support commit
- (FEATURED) Vega20 enablement + kfd support commit, commit, commit, commit, commit, commit, commit
- ACP powergating improvements commit, commit, commit
- ABGR/XBGR display support commit, commit, commit
- VCN jpeg support commit
- xGMI support commit, commit
- Ycbcr 4:2:0 support commit
- Stereo 3D support in VSC commit
- Support reading hw state from debugfs file commit
- Implement AMDGPU_PP_SENSOR_MIN/MAX_FAN_RPM so user can query rpm range commit
- Add DMCU firmware loading for Raven (used for ABM and PSR) commit commit, commit
- Add support for LVDS commit
- Add fan RPM setting via sysfs commit
- add some additional vega10 pci ids commit
- Add DPG mode support for vcn 1.0 commit
- add GDS, GWS and OA debugfs files commit
- print smc feature mask in debugfs amdgpu_pm_info commit
- Add support for hw_state logging via debugfs commit
- Add get_hive_id interface in kfd2kgd commit, commit
- amdkfd
  - Add new iolink type defines commit
  - Add wavefront context save state retrieval ioctl commit
  - add new vega10 pci ids commit
  - kfd expose the hive_id of the device through its node properties commit
exynos
- out-bridge support for LVDS bridge driver commit
- Samsung 16x16 tiled format support commit, commit, commit
- Plane alpha and pixel blend mode support commit, commit
intel
- Turn off resource streamer API commit
- More Icelake enablement + DMC firmware
- Full PPGTT for Ivybridge, Haswell and Valleyview commit
- DDB distribution based on resolution commit
- Add a new CFL PCI ID commit
- Add PSR mode/revision to debugfs commit
- Add debugfs support to force a downgrade to PSR1 mode commit
mali-dp
- Implement plane alpha and pixel blend on malidp commit
mediatek
- HDMI output support on mt2701 and mt7623 commit
- Add dpi driver for mt2701 and mt7623 commit
- Add support for SPDIF audio in HDMI commit
nouveau
- Add DisplayPort CEC-Tunneling-over-AUX support commit
- Initial HDMI 2.0 support commit
rockchip
- PX30 support commit
- rgb output interface support commit
sun4i
- R40 TCON support commit
- Add support for A64 mixers commit
- R40 HDMI support commit
- Add dithering support for RGB565/RGB666 LCD panels commit
tegra
- Add Tegra194 support commit
bridge
- Add support for sn65dsi86 bridge driver commit
- tc358764: Add DSI to LVDS bridge driver commit
vkms
- GEM support commit
- Add cursor plane support commit, commit
rcar-du
- Add r8a77990 and r8a77995 device support commit
- Interlaced modes on Gen3 commit
- D3 and E3 SoC support commit
virtio-gpu
- vmap support for PRIME objects commit
- Add iommu support commit
backlight
- Remove ld9040 driver commit
- Remove s6e63m0 driver commit

12.2. Storage

nvme: Add support for P2P memory commit, commit, commit, commit
nvmet_fc: support target port removal with nvmet layer commit
cxgb4i: add DCB support for iSCSI connections commit
myrb: Add Mylex RAID controller commit, commit
qla2xxx: Add mode control for each physical port commit
ufs: Add API to execute raw upiu commands commit

12.3. Drivers in the Staging area

media: platform: Add Cedrus VPU decoder driver commit
comedi: add interface to ni routing table information commit
comedi: add new device-global config interface commit
comedi: ni_660x: Add NI PCI-6608 to list of supported devices commit
comedi: ni_mio_common: implement global pfi, rtsi routing commit
comedi: ni_mio_common: implement new routing for TRIG_EXT commit
comedi: ni_mio_common: implement output selection of GPFO_{0, 1} commit
comedi: ni_routing: Add NI signal routing info commit
comedi: tio: implement global tio/ctr routing commit
dgnc: delete the driver commit
vboxvideo: Atomic phase 3: Switch last bits over to atomic commit
iio:ad7606: Add support for the ad7605-4 commit

12.4. Networking

dpaa2-eth: Move DPAA2 Ethernet driver from staging to drivers/net commit
Bluetooth
- btbcm: Add entry for BCM4335C0 UART bluetooth commit
- btrtl: Add support for RTL8822C with USB interface commit
- btusb: Add support for 0cf3:535b QCA_ROME device commit
FDDI: defza
- Add support for DEC FDDIcontroller 700 TURBOchannel adapter commit
- Support capturing outgoing SMT traffic commit
RDMA/hns: adds atomic and cm of vlan device function for hip08 as well as optimize some codes for post send verbs commit, commit, commit, Add enable judgement for UD vlan commit
aquantia: implement EEE support commit, implement WOL support commit
ath10k
- Add support for wifi QMI client handshake commit, commit, commit, commit, commit
- Add debugfs entry to enable extended tx stats commit, add debugfs support to dump per sta tx stats commit, add debugfs support to get power save state change of STA commit
- Add extended per sta tx statistics support commit
- Add support for configuring management packet rate commit
- Enable pktlog for WCN3990 target commit
- Add High Latency support commit, commit, commit
- Support NET_DETECT WoWLAN feature commit
- Support extended board data download for dual-band QCA9984 commit
ath9k
- Add back support for using active monitor interfaces for tx99 commit
- Add counters for good and errorneous FFT/spectral frames commit
- Add reset for airtime station debugfs commit
bnxt_en
- Add 57500 new chip ID and basic structures commit
- Add PCI ID for BCM57508 device commit
- Add additional extended port statistics commit
- Add maximum extended request length fw message support commit
brcmfmac: add CYW89342 mini-PCIe device commit
cxgb4
- Add thermal zone support commit
- Add per rx-queue counter for packet errors commit
dpaa2-eth: Add ethtool support for flow classification commit
dsa: Add Lantiq / Intel DSA driver for vrx200 commit
dsa: b53: Add SerDes support commit
ena: enable Low Latency Queues commit, commit, commit, commit
fm10k: add missing device IDs to the upstream driver commit
hinic: add checksum offload and TSO support commit
hns3
- Support of Flow Director for HiP08 Rev2 SoC commit, commit, commit, commit, commit, commit, commit
- Adds support of RSS for Rev 2 commit, commit, commit, commit
- Adds support of RAS Error Handling commit, commit, commit, commit, commit, commit, commit
- Add default irq affinity commit
- Add egress/ingress vlan filter for revision 0x21 commit
- Add support for hns3_nic_netdev_ops.ndo_do_ioctl commit
- Add support for sctp checksum offload commit
hv_netvsc: Add support for LRO/RSC in the vSwitch commit
i40e: add AF_XDP zero-copy support commit, commit
ibmvnic: Add ethtool private flag for driver-defined queue limits commit
ice
- Add SR-IOV support and some feature updates commit, commit, commit, commit, commit, commit, commit, commit
Add support for Tx hang, Tx timeout and malicious driver detection commit
Add support for dynamic interrupt moderation commit
Implement ethtool hook for RSS switch commit
Implement handlers for ethtool PHY/link operations commit
igc: Add skeletal frame for Intel(R) 2.5G Ethernet Controller support commit
iwlwifi
- Add d3 debug data support commit
- Add debugfs to send host command commit
- mvm: implement extended HE-MU sniffer API commit
- mvm: support Coex Schema 2 commit, commit
- Support new WoWLAN status FW API commit
- Support new reduce tx power FW API commit
ixgbe
- Add AF_XDP zero-copy support commit, commit
- IPsec hardware offload for 10Gbe VF commit, commit, commit, commit, commit, commit, commit, commit
lantiq: Add Lantiq / Intel VRX200 Ethernet driver commit
liquidio: Add the features to show FEC settings and set FEC settings commit
mlx5: Extended DEVX on IB commit, commit, commit, commit
RDMA/mlx5
- Add the ability to attach recently added flow actions to flow steering rules: modify header and packet reformat
- Flow actions to mutate packets commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
mlx5: Add Fast teardown support commit
mlx5e
- Add ethtool control of ring params to VF representors commit
- Add new counter for aRFS rule insertion failures commit
- Added 'raw_errors_laneX' fields to ethtool statistics commit
- Allow reporting of checksum unnecessary commit
- Enable multi-queue and RSS for VF representors commit
- Enable reporting checksum unnecessary also for L3 packets commit
- Enable stateless offloads for VF representor netdevs commit
- Ethtool driver callback for query/set FEC policy commit
- Ethtool steering, Support masks for l3/l4 filters commit
- Expose ethtool rss key size / indirection table functions commit
- IPoIB, Add ndo stats support for IPoIB child devices commit
- IPoIB, Add ndo stats support for IPoIB netdevices commit
- Support offloading tc priorities and chains for eswitch flows commit
mlxsw: Add VxLAN support commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
mt76: report firmware version using ethtool commit
mt76x0
- Add mt7650 PCI ID commit
- Report firmware version using ethtool commit
mt76x2u: Add support for Alfa AWUS036ACM commit
mvneta
- Add support for 2500Mbps SGMII commit
- Enable NETIF_F_RXCSUM by default commit
mvpp2: support XPS by mapping TX queues to CPUs commit
nfp
- bpf: add support for BPF-to-BPF function calls commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit,
- Add support for NFP5000 commit
nixge: Add support for 64-bit platforms commit
Add a new driver for Marvell's OcteonTX2 SOC's Resource virtualization unit (RVU) admin function driver commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
phy
- micrel: add Microchip KSZ9131 initial driver commit
- mscc: add ethtool statistics counters commit
- mscc: add support for VSC8574 PHY commit
- mscc: add support for VSC8584 PHY commit
qed
- Add driver support for 20G link speed commit
- Add support for virtual link commit
- Add supported link and advertise link to display in ethtool commit
qede: Add driver support for 20G link speed commit
qtnfmac
- Add support for scan dwell time configuration commit
- Add support for scan flush commit
- Implement dump_station support for STA mode commit
r8169: add support for Byte Queue Limits commit
rtl8xxxu: Add rtl8188ctv support commit
systemport: Turn on offloads by default commit
wil6210
- Add FT roam support for AP and station commit
- Add support for channel 4 commit
- Rremove reset file from debugfs commit
wlcore: Add support for optional wakeirq commit

12.5. Audio

realtek: Add support for Acer Aspire C24-860 headset mic commit
realtek: Support ALC300 commit
Add support for AMD Stoney Ridge commit
usb-audio: Add vendor and product name for Dell WD19 Dock commit
ASoC
- Add support to card rebind commit
- Add driver for PROTO Audio CODEC (with a WM8731) commit
- Intel: Boards: Add KBL Dialog Maxim I2S machine driver commit
- Intel: Boards: Machine driver for SKL+ w/ HDAudio codecs commit
- codecs: tas5720: add TAS5722 TDM slot width setting support commit, add TAS5722 specific volume control commit
- hdac_hda: add asoc extension for legacy HDA codec drivers commit
- meson: add axg pdm input commit
- nau8822: new codec driver commit
- pcm3060: Add codec driver commit
- pcm3168a: add I2S/Left_J TDM support commit
- rsnd: add support for 8 bit S8 format commit
- rsnd: add support for the DSP_A/DSP_B formats commit
- sta32x: Add support for XTI clock commit
- sunxi: Add new driver for Allwinner A64 codec's analog path controls commit

12.6. Tablets, touch screens, keyboards, mouses

HID
- hid-bigbenff: driver for BigBen Interactive PS3OFMINIPAD gamepad commit
- ite: Add USB id match for another ITE based keyboard rfkill key quirk commit
- microsoft: Add rumble support for Xbox One S controller commit
- multitouch: Add pointstick support for Cirque Touchpad commit
elan_i2c: add ACPI ID for Lenovo IdeaPad 330-15ARR commit
elan_i2c: add ELAN0620 to the ACPI table commit
elan_i2c: add support for ELAN0621 touchpad commit
synaptics: add PNP ID for ThinkPad P50 to SMBus commit
synaptics: enable SMBus for HP 15-ay000 commit

12.7. TV tuners, webcams, video capturers

Implement media requests commit, commit
Add imx319 camera sensor driver commit
Add imx355 camera sensor driver commit
dvb-frontends: add LNBH29 LNB supply driver commit
imx-pxp: add i.MX Pixel Pipeline driver commit
uapi/linux/media.h: add request API commit
Add definition for the Sunxi tiled NV12 format commit
Add definitions for MPEG-2 slice format and metadata commit
vivid: Add 16-bit bayer to format list commit, support 480p for webcam capture commit

12.8. Universal Serial Bus

Add uevent for over-current commit
typec: ucsi: add support for Cypress CCGx commit
export firmware port location in sysfs commit
EHCI: make ehci-mv a separate driver commit
appledisplay: Add 27" Apple Cinema Display commit
cdc-acm: add entry for Hiro (Conexant) modem commit
dwc3: exynos: Add support for Exynos5433 variant with all clocks commit
gadget: udc: renesas_usb3: add support for r8a77990 commit
gadget: uvc: configfs: Add bFormatIndex attributes commit, add bFrameIndex attributes commit, add interface number attributes commit
usbtmc: usbtmc: Changes needed for compatible IVI/VISA library commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
xhci-mtk: supports bandwidth scheduling with multi-TT commit
serial: option
- add HP lt4132 commit
- add GosunCn ZTE WeLink ME3630 commit
- add Simcom SIM7500/SIM7600 (MBIM mode) commit
- add Fibocom NL668 series commit
- add Telit LN940 series commit

12.9. Serial Peripheral Interface (SPI)

spi: add support for Amazon's Alpine spi controller commit
Introduce new driver for Qualcomm QuadSPI controller commit
at91-usart: Add driver for at91-usart as SPI commit
dw-mmio: add MSCC Jaguar2 support commit
mediatek: add spi slave for Mediatek MT2712 commit
omap2-mcspi: Add slave mode support commit
spi-geni-qcom: Add SPI driver support for GENI based QUP commit
spi-mem: add stm32 qspi controller commit
sprd: Add SPI driver for Spreadtrum SC9860 commit

12.10. Watchdog

Add support for Armada 37xx CPU watchdog commit
w83627hf_wdt: Support NCT6796D, NCT6797D, NCT6798D commit

12.11. Serial

Add ISO7816 infrastructure commit
sh-sci: Add earlycon for R7S9210 commit
8250_uniphier: add auto-flow-control support commit
atmel: add ISO7816 support commit

12.12. ACPI, EFI, cpufreq, thermal, Power Management

ACPI
- LPSS: Add alternative ACPI HIDs for Cherry Trail DMA controllers commit
- ADXL: Add address translation interface using an ACPI DSM commit
- TAD: Add low-level support for real time capability commit
efi: add API to reserve memory persistently across kexec reboot commit
tools: sleepgraph and bootgraph: upgrade to v5.2 commit, commit
cpufreq: intel_pstate: Add base_frequency attribute commit, commit
thermal
- hisi: Add multiple sensors support commit
- hisi: Add the dual clusters sensors for hi3660 commit
- Add stm32 thermal driver commit

12.13. Real Time Clock (RTC)

ds1307: add frequency_test_enable attribute on m41txx commit
ds1307: add offset sysfs for mt41txx chips commit
abx80x: add basic watchdog support commit
rv8803: add Epson RX8803 support commit

12.14. Voltage, current regulators, power capping, power supply

power: supply
- Add Spreadtrum SC2731 charger support commit
- bq25890_charger: Add the BQ25896 part commit
- bq27xxx: Add support for BQ27411 commit
- reset: qcom-pon: Add pms405 pon support commit
regulator
- Add consumer-requested load in regulator_summary commit
- Add the opmode to regulator_summary commit
- mfd: Support ROHM BD71847 power management IC commit
- lochnagar: Add support for the Cirrus Logic Lochnagar commit
- qcom: Add PMS405 regulators commit
- stpmic1: add stpmic1 regulator driver commit

12.15. Pin Controllers (pinctrl)

bcm: add Northstar driver commit
ingenic: Add support for the JZ4725B commit
mediatek: add MT6765 pinctrl driver commit
mediatek: add MT7623 pinctrl driver based on generic pinctrl binding commit
mediatek: add MT8183 pinctrl driver commit
mediatek: add pinctrl-paris that implements the vendor dt-bindings commit
meson-g12a: add pinctrl driver support commit
nuvoton: add NPCM7xx pinctrl and GPIO driver commit
qcom: Add qcs404 pinctrl driver commit
qcom: Add sdm660 pinctrl driver commit
renesas: Renesas RZ/N1 pinctrl driver commit
sh-pfc: r8a7791: Add r8a7744 support commit
sh-pfc: r8a7796: Add R8A774A1 PFC support commit
sh-pfc: r8a77990: Add R8A774C0 PFC support commit

12.16. Multi Media Card (MMC)

mediatek: add MT8183 MMC driver support commit
mmci: add stm32 sdmmc variant commit
sdhci-iproc: Add ACPI support commit
sdhci-sprd: Add Spreadtrum's initial host controller commit
sdhci: Add Auto CMD Auto Select support commit
tegra: Enable UHS and HS200 modes for Tegra186 commit
tegra: Enable UHS and HS200 modes for Tegra210 commit
uniphier-sd: add UniPhier SD/eMMC controller driver commit

12.17. Memory Technology Devices (MTD)

rawnand: toshiba: Add support for Toshiba Memory BENAND (Built-in ECC NAND) commit
rawnand: Remove docg4 commit
spi-nor: add support to non-uniform SFDP SPI NOR flash memories commit
spi-nor: intel-spi: Add support for Intel Ice Lake SPI serial flash commit

12.18. Industrial I/O (iio)

adc: Add QCOM SPMI PMIC5 ADC driver commit
adc: add support for mcp3911 commit
adc: sc27xx: Add raw data support commit
adxl372: New driver for Analog Devices ADXL372 Accelerometer commit
dac: add support for ltc1660 commit
imu: st_lsm6dsx: add support to LSM6DSO commit
proximity: Add driver support for ST's VL53L0X ToF ranging sensor commit
tsl2772: add support for avago,apds9930 commit
adxl372: Add filter bandwidth support commit
adxl372: Add sampling frequency support commit

12.19. Inter-Integrated Circuit (I2C)

Add i2c bus driver for NVIDIA GPU commit

12.20. Hardware monitoring (hwmon)

nct6775: Add support for NCT6798D commit
nct6775: Add support for NCT6797D commit
lm75: Add MAX31725/6 support commit
pmbus/ltc2978: Add support for LTM4686 uModule commit

12.21. General Purpose I/O (gpio)

add single-register GPIO via CREG driver commit
ingenic: Remove driver commit

12.22. Leds

Introduce LED pattern trigger commit
sc27xx: Add pattern_set/clear interfaces for LED controller commit
add Panasonic AN30259A support commit

12.23. DMA engines

dma-jz4780: Add support for the JZ4725B SoC commit
dma-jz4780: Add support for the JZ4740 SoC commit
dma-jz4780: Add support for the JZ4770 SoC commit
dw: Add alternative ACPI HIDs for Cherry Trail DMA controllers commit
fsl-edma: add ColdFire mcf5441x edma support commit
owl: Add Slave and Cyclic mode support for Actions Semi Owl S900 SoC commit

12.24. Cryptography hardware acceleration

caam/qi2: add DPAA2-CAAM driver commit, commit, commit
cavium/nitrox: Added support for SR-IOV configuration commit
cavium/nitrox: add support for per device request statistics commit
cavium/nitrox: added support to identify the NITROX device partname commit
cavium/nitrox: updated debugfs information commit
ccp: add timeout support in the SEV command commit
s5p-sss: Add aes-ctr support commit

12.25. PCI

P2PDMA: Support peer-to-peer memory. Recommended LWN article: Device-to-device memory-transfer offload with P2PDMA. commit, commit
imx: Add PME_Turn_Off support commit
imx: Initial imx7d pm support commit

12.26. Non-Transparent Bridge (NTB)

idt: Add basic hwmon sysfs interface commit

12.27. Clock

Add Ingenic jz4725b CGU driver commit
actions: Add Actions Semi Owl SoCs Reset Management Unit support commit
actions: Add Actions Semi S700 SoC Reset Management Unit support commit
actions: Add Actions Semi S900 SoC Reset Management Unit support commit
at91: add at91sam9260 PMC driver commit
at91: add at91sam9rl PMC driver commit
at91: add at91sam9x5 PMCs driver commit
at91: add sama5d2 PMC driver commit
at91: add sama5d4 pmc driver commit
qcom: Add Global Clock controller (GCC) driver for SDM660 commit
qcom: Add HFPLL driver commit
qcom: Add KPSS ACC/GCC driver commit
qcom: Add Krait clock controller driver commit
qcom: Add camera clock controller driver for SDM845 commit
qcom: Add support for Krait clocks commit
qcom: Add support for RCG to register for DFS commit
qcom: gcc: Add global clock controller driver for QCS404 commit
renesas: cpg-mssr: Add R7S9210 support commit
renesas: cpg-mssr: Add r8a774a1 support commit
renesas: r8a7743: Add r8a7744 support commit
c-sky: Add C-SKY SMP timer commit
c-sky: Add gx6605s SOC system timer commit
Add ZynqMP clock driver commit

12.28. Firmware

dcdbas: Add support for WSMT ACPI table commit
imx: add SCU firmware driver support commit
imx: add misc svc support commit
meson_sm: Add serial number sysfs entry commit
xilinx: Add Zynqmp firmware driver commit
xilinx: Add debugfs for query data API commit
xilinx: Add debugfs interface commit
xilinx: Add zynqmp IOCTL API for device control commit

12.29. IOMMU

arm-smmu-v3: Add support for non-strict mode commit
arm-smmu: Support non-strict mode commit
dma: Add support for non-strict mode commit
io-pgtable-arm-v7s: Add support for non-strict mode commit
io-pgtable-arm: Add support for non-strict mode commit
vt-d: Add debugfs support for Interrupt remapping commit
vt-d: Add debugfs support to show context internals commit
vt-d: Add debugfs support to show register contents commit
vt-d: Enable base Intel IOMMU debugfs support commit
Add "iommu.strict" command line option commit

12.30. PHY

Add driver for Cadence MHDP DisplayPort SD0801 PHY commit
add Rockchip Innosilicon hdmi phy commit
add driver for Microsemi Ocelot SerDes muxing commit
phy-pxa-usb: add a new driver commit
socionext: add PCIe PHY driver support commit
socionext: add USB2 PHY driver for UniPhier SoC commit
socionext: add USB3 PHY driver for UniPhier SoC commit

12.31. IRQ chip

irq-mvebu-icu: Add support for System Error Interrupts (SEI) commit
irq-mvebu-sei: Add new driver for Marvell SEI commit
add C-SKY APB bus interrupt controller commit
add C-SKY SMP interrupt controller commit

12.32. Various

edac: Add EDAC driver support for QCOM SoCs commit
eeprom: New ee1004 driver for DDR4 memory commit
gsmi: Add GSMI commands to log S0ix info commit
remoteproc: qcom: Introduce Non-PAS ADSP PIL driver commit
reset: qcom: PDC Global (Power Domain Controller) reset controller commit
slimbus: core: add support to uevent commit
soundwire: Add support for multi link bank switch commit

13. List of merges

14. Other news sites

LWN's merge window part 1, part 2, Development statistics
Phoronix The Many New Features of The Linux 4.20 Kernel
heise.de (German): Linux 4.20 freigegeben: Performance-Optimierungen und neue Treiber
Linux v4.20: Performance Goodies