Yes, not counting fairly serious bugs, we stick to one kernel per major release.
Do you have a link to the exact change that fixes your issue?
(let's face it, 3.0.21 is quite in the early stages of a very new 3.0 kernel)
How do you come to that? The stable updates usually only go to 7-8, the longterm/enterprise lines like 3.0 are exceptions.
Yes, seems support for the e6xx Atom series was added in kernel 3.0.32:
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.0.32 pch_gbe: support ML7831 IOH
commit 7756332f5b64c9c1535712b9679792e8bd4f0019 upstream.
Support new device OKI SEMICONDUCTOR ML7831 IOH(Input/Output Hub)
ML7831 is for general purpose use.
ML7831 is companion chip for Intel Atom E6xx series.
ML7831 is completely compatible for Intel EG20T PCH.
This is just an example, I've seen newer kernels in the 3.0.xx series add support for more architectures as well. Just wanted to make you guys aware of it. And about 3.0.21, I just assumed that since 3.0 was a total revamp of the Linux kernel that 3.0.21 may still be a bit buggy. I keep track of the changelogs at kernel.org with every kernel update and compared to the 2.6.xx kernels of the past, there are seemingly many more fixes with every release of a 3.0.xx kernel. I'm sure 3.0.21 will hold up just fine, it works great on every other unit I have tested it on
Again, sorry for going off topic here ...