This question is similar to this one: What unique enhancements and features has Ubuntu brought to the Linux Community but in this case it is directed towards what has Ubuntu contributed to the official Linux Kernel.

For example, many times I hear about Intel contributing to patches for the Linux Kernel like the RC6 latest patches and any other related to the recent Sandy/Ivy Bridges. In another group, Android did an upstream patch and a lot of ARM patches have also come to the Linux Kernel.

I have seeing only a small percent of companies and groups that have contributed to the Linux Kernel (http://kernel.org) but I want to know, since the beginning of Ubuntu till now, what has Ubuntu contributed to the Linux Kernel in regards to any aspect of the kernel.

For Kernel information I typically go to http://kernelnewbies.org and http://kernel.org