Linux 5.5 has not been released.
This changelog has not been completed. Meanwhile, you can read about this Linux release on:
Phoronix Linux 5.5 Feature Overview
Alternatively, you can take a look at the Pull Requests:
1. PCI
AER: Add PoisonTLPBlocked to Uncorrectable error counters commit
ASPM: Add sysfs attributes for controlling ASPM link states commit, commit
DPC: Add pcie_ports=dpc-native to allow DPC without AER control commit
Add pci=hpmmiosize and pci=hpmmioprefsize parameters commit
amlogic: meson: Add support for G12A commit
rpaphp: Add drc-info support for hotplug slot registration commit
vmd: Add device id for VMD device 8086:9A0B commit
2. Non-Transparent Bridge (NTB)
Add Hygon Device ID commit
3. Thunderbolt
Add Thunderbolt 3 support for the software connection manager. It is currently only used in Apple systems. Previously the driver started the firmware connection manager on those but it is not necessary anymore in this release (we still leave user an option to start the firmware in case there are problems with the software connection manager). This includes: Expose 'generation' attribute under each device in sysfs, lane bonding support, expose link speed and width in sysfs, display Port handshake needed for Titan Ridge devices, display Port pairing and resource management, and display Port bandwidth management commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit, commit
4. FRU Support Interface (FSI)
5. Clock
Add common clock driver for BM1880 SoC commit
Ingenic: Add CGU driver for X1000 commit
meson: axg_audio: add sm1 support commit
qcom: Add Global Clock controller (GCC) driver for SC7180 commit
qcom: Add MSM8998 GPU Clock Controller (GPUCC) driver commit
qcom: Add Q6SSTOP clock controller for QCS404 commit
qcom: clk-rpmh: Add support for RPMHCC for SC7180 commit
renesas: cpg-mssr: Add r8a774b1 support commit
renesas: r8a7796: Add R8A77961 CPG/MSSR support commit
tegra: Add Tegra20/30 EMC clock implementation commit
6. PHY ("physical layer" framework)
phy/rockchip: Add support for Innosilicon MIPI/LVDS/TTL PHY commit
Add USB2 PHY driver for Marvell MMP3 SoC commit
allwinner: add phy driver for USB3 PHY on Allwinner H6 SoC commit
qcom-qmp: Add SM8150 QMP UFS PHY support commit
tegra: xusb: Add XUSB dual mode support on Tegra210 commit
tegra: xusb: Add usb3 port fake support on Tegra210 commit
tegra: xusb: Add vbus override support on Tegra186 commit and Tegra210 commit
7. Various
counter: new TI eQEP driver commit
firmware: broadcom: add OP-TEE based BNXT f/w manager commit
firmware: qcom: scm: add OCMEM lock/unlock interface commit
firmware: qcom: scm: add support to restore secure config to qcm_scm-32 commit
firmware: xilinx: Add support for versal soc commit
fpga: dfl: fme: add power management support commit
fpga: dfl: fme: add thermal management support commit
habanalabs: Add a new H/W queue type commit
habanalabs: add opcode to INFO IOCTL to return clock rate commit
habanalabs: export uapi defines to user-space commit
habanalabs: expose card name in INFO IOCTL commit
interconnect: qcom: add msm8974 driver commit
iommu/ioasid: Add custom allocators commit
iommu: Add I/O ASID allocator commit
iommu: Introduce guest PASID bind function commit
iommu: arm-smmu-impl: Add sdm845 implementation hook commit
irqchip: Add support for Layerscape external interrupt lines commit
mailbox: imx: add support for imx v1 mu commit
mei: add trc detection register to sysfs commit
mei: bus: add more client attributes to sysfs commit
mei: me: add comet point V device id commit
memory: Add DMC driver for Exynos5422 commit
memory: Extend of_memory with LPDDR3 support commit
memory: tegra: Introduce Tegra30 EMC driver commit
misc: fastrpc: add mmap/unmap support commit
misc: rtsx: Add support for RTS5261 commit
nfc: pn533: Add autopoll capability commit
nfc: pn533: add UART phy driver commit
powercap/intel_rapl: add support for CometLake Mobile commit
powercap/intel_rapl: add support for Cometlake desktop commit
ptp: Add a ptp clock driver for IDT ClockMatrix commit
remoteproc: qcom_q6v5_mss: Add support for MSM8998 commit
reset: add support for the Meson-A1 !SoC Reset Controller commit
reset: meson-audio-arb: add sm1 support commit
serdev: Add ACPI devices by ResourceSource field commit
soc/tegra: fuse: Implement nvmem device commit
soc/tegra: pmc: Add wake event support on Tegra210 commit
soc/tegra: pmc: Configure core power request polarity commit
soc/tegra: pmc: Configure deep sleep control settings commit
soc/tegra: pmc: Support wake events on more Tegra SoCs commit
soc/tegra: regulators: Add regulators coupler for Tegra20 commit
soc/tegra: regulators: Add regulators coupler for Tegra30 commit
soc: amlogic: meson-gx-socinfo: Add A1 and A113L IDs commit
soc: amlogic: meson-gx-socinfo: Add S905X3 ID for VIM3L commit
soc: at91: Add Atmel SFR SN (Serial Number) support commit
soc: fsl: add RCPM driver commit
soc: qcom: add OCMEM driver commit
soc: qcom: socinfo: add sdm845 and sda845 soc ids commit
soc: renesas: Add Renesas R8A774B1 config option commit
soc: renesas: Identify RZ/G2N commit
soc: renesas: rcar-rst: Add support for RZ/G2N commit
soc: renesas: rcar-sysc: Add R8A77961 support commit
soc: renesas: rcar-sysc: Add r8a774b1 support commit
soc: samsung: Add Exynos Adaptive Supply Voltage driver commit
soc: ti: add initial PRM driver with reset control support commit
w1: new driver. DS2430 chip commit
8. List of Pull Requests
9. Other news sites
Phoronix Linux 5.5 Feature Overview