A) OK. In that case instead of a regression in the linux kernel itself we'd have a regression in the way one (more?) distribution are configuring their kernels. From the point of view of the users, it makes little practical difference.
B) I don't know. Maybe, I guess? It would have to be quite an important component of the system, and again, for users it would make not much difference. The way to test this would have to install 2 kernel versions. Some user in the forum did this and found a difference. I did and found none (but I can't measure anything).
C) It's not like 2.6.37 required a new version of PowerTop. PowerTop required a recent kernel for some of its features to work. I don't see how this is relevant.
D) That the kernel doesn't tweak itself is a constant in these tests, therefore it can't explain the observed differences.
We'll know soon enough, I guess.
I'd just like to stress that thanks to the Phoronix Test Suite and how its widely spread, this problem can be narrowed down to when exactly the issue was introduced much faster. Without it the amount of code to inspect would have been drastically more important, IMHO.
Thanks to Michael for inspecting this issue!
This doesn't mean that the configuration problem wouldn't be visible across distributions, because none of them (with the exception of a few designed for portables like mine, Fuduntu) reconfigure the running kernel when the applied power state changes.
Thank you for bringing attention to this regression. Without Phoronix, this regression would have received very little, if any, attention.
Being a mobile user, I would definitely love to see the devs get to the bottom of this issue, whether it be an actual regression in the kernel, or a serious misconfiguration, either way, it still affects us and needs to be looked at.
Thanks again for PTS!
Translation: They're not willing to pay me any money so that I divulge to them the commit id where the 'regression' was introduced.It doesn't appear that they are devoting any resources to getting the issue resolved but it looks like they will be waiting for a fix to appear upstream in the stable series or in 2.6.39 and then to have that back-ported into an Ubuntu 11.04 SRU update.
Scared by this phoronix article, i decided to give 18.104.22.168 from archlinux packages a try.
Well, on this little asus eeepc 1005ha, this kernel shines, really.
It went from about 6.1-6.5W to 5.7..6.2W just idling.
What can i say, the bug of course isn't triggered for me.