Short overview (for news sites, etc)
Linux 2.6.20 greatly improves kdump (http://news.zdnet.co.uk/software/0,1000000121,39285165,00.htm ); KVM (http://kvm.sourceforge.net) for Intel with VT and AMD with SVM hardware virtualization; Support for relocatable kernels, for backups with kernel panics.
Important things (AKA: ''the cool stuff'')
- Asynchronous SCSI scanning
- Multithreaded USB probing
- New 300Hz option. Good because it evenly divides PAL and NTSC framerates
- HID Layer split: Allows things other than USB to use the HID layer (Bluetooth)
- Relative atime support (only updates the atime if the previous atime is older than the mtime or ctime)
- I/O Accounting
Drivers
- Removal of the crusty FTape driver
- Add support for Moxa SmartIO multiport serial cards
- ohci1394: steps to implement suspend/resume
- allow usb hubs to have up to 31 children
- Add support for Korenix 16C950-based PCI cards (serial cards)
HW Mon
- Add support for the Fintek F71872F/FG chip
- New Winbond W83793 hardware monitoring driver
- New National Semiconductor PC87427 hardware monitoring driver
Network
- Atmel MACB support
Add NetXen 1G/10G ethernet driver.
- e1000: New hardware support
- forcedeth: power management support
PATA
- Add support for Winbond, Marvel, and others
- Some suspend/resume support added
Sensors
- Add support for Apple Motion Sensors
- Support for National Semiconductor PC87427 Super-I/O chip
- Support for Winbond W83793 sensors
Sound
- Remove obsolete OSS drivers that already have ALSA replacements
Video
- Add support for DMC TSC-10/25 devices
- Add support for Philips UCB1400 touchscreen
- Framebuffer support for IBM GXT4500P adaptor
- Ability to set Geode framebuffer size
- DRM i915 updates
- V4L
- Add support for Pinnacle 310i
- Added support for a ASUSTEK P7131 Dual DVB-T variant
- Add support for the Compro Videomate DVB-T200A
Other stuff
- Add sysrq_always_enabled boot option
- Make sure the initroot filesystem is populatated late enough
Arch-independent changes in the kernel core
Add support for Log2 mechanism [http://lwn.net/Articles/203596/]
Driver core: add notification of bus events [http://lkml.org/lkml/2006/12/1/297]
- sched: optimize activate_task for RT task
Architecture-specific changes
- rtc-sh: alarm support
- ARM
- Support to change MX1 CPU frequency at runtime.
- Support for Atmel AT91SAM9260-EK (and 61) boards
- Some more suspend to RAM support
- i386
- Add support for a relocatable kernel. This is useful for kexec panics and another kernel being loaded.
- Add support to compile for Core2
- MIPS
- Use "long" for 64-bit values on 64-bit kernel.
- PowerPC
- Refactor 64 bit DMA operations
- Add support for EFIKA boards
- Add support for the Sony Playstation 3
- S390
- cpu shutdown rework
- New DASD feature for ERP related logging: no longer have to recompile to change ERP logging on/off
- x86_64
- Add support to compile for Core2
- Altix: Some ACPI support
Filesystems
- Relative atime support for ocfs2
- DebugFS: inotify support
- optimize o_direct on block devices
Networking
CPU Freq
- Add support for CN400 when ACPI C3 isn't available.
move kallsyms data to .rodata