Android Kernel Versions

2.6.23
The first-generation Google-TV products (released about November, 2010) used kernel version 2.6.23. It is speculated that this is due to existing binary driver support for the Intel chipsets used in those products.

2.6.25
The original (version 1.0) of Android for the G1/ADP1 used Linux version 2.6.25

2.6.27
The 1.5 release of Android (cupcake) for the G1/ADP1 used Linux version 2.6.27

2.6.29
As of September, 2009, the kernel/common.git tree for Android has a 2.6.29 kernel. Donut uses this kernel.

2.6.32
As of July 2010, the kernel/common.git tree for Android has a 2.6.32 kernel. This kernel is used by Froyo.

2.6.35
Gingerbread used kernel version 2.6.35.

Selecting a kernel tree for a new port
This article has good information on porting Android to a new device. Note that it debates which kernel tree is appropriate to start with, for porting to a new device:
 * http://www.linuxfordevices.com/c/a/Linux-For-Devices-Articles/Porting-Android-to-a-new-device/

Android git kernel trees
As of July 2010, the android repository on kernel.org had the following kernel trees:


 * kernel/common.git : This is the kernel tree that matches what is put into official Android products by Google or its partners
 * kernel/experimental.git : some experimental stuff
 * kernel/linux-2.6.git : mirror of Linus' kernel tree. This is a reference for the kernel tree used in Android
 * kernel/lk.git : not a kernel tree, but a bootloader
 * kernel/msm.git : kernel for MSM (Qualcomm chip used in many HTC products)
 * kernel/omap.git : mirror of kernel tree maintained by texas instruments., supporting OMAP chips. usually based on kernel.org latest version, android products w OMAP chip can use this kernel port.
 * kernel/tegra.git : nvidia kernel tree