The new Linux Kernel 4.0 is average progress on the code
Besides the minimum improvements for support on a new hardware, correcting bugs and minimal performance improvement, it can not tell that it is something spectacular.
One of the best things of this upgrade is that it allows to perform upgrades without having to reboot the system. For some users a restart is 30 seconds work, but when it comes to servers and advanced devices a “plain” reset procedure that is known to take away a few hours.
Though still new, the ability to update without restarting the system will be improved in future editions of the kernel.
Additionally, there are improvements for Linux that is installed on the Playstation 3 and improvements to the Radeon DisplayPort Audio drivers.
Improvements to Intel ‘Skylake’ platform
Intel Quark SoC suppor
Various patches to improve Linux running on a Playstation 3
TOpen-source AMD Radeon driver supports DisplayPort Audio
Various misc HID driver tweaks, including Lenovo compact keyboards, Wacom Cintiq 27QHD
Toshiba power settings driver adds USB sleep/charge functionality, rapid charge, sleep w/ music, etc
File System tweaks, including F2FS, BtrfFS, etc