On Thu, 28 Jun 2007 21:26:14 +0100
Raymond Meyer <raymond.meyer@rambler.ru> wrote:

> Hi, I noticed NetBSD-current has envctrl for Sun E450. Is it possible to
> manually adjust the CPU temp -> Fan Speed mapping? If yes, will this work only
> with NetBSD or is it also possible to make it work with Solaris?

It is possible, and fairly easy to implement. One way would be to
have a sysctl variable for setting the fan voltage, and a safety
threshold temperature at which the fans go to full speed. I've thought
about implementing this since my fans sometimes spin at an RPM that
causes annoying resonance noise.
Another way would be to have a temperature-to-voltage table compiled
into the kernel instead of reading it from the the openboot properties.
I'm not a big fan of this idea since frying your hardware becomes
alot easier.
I don't know about Solaris, but the temperature tables are OPB
properties so I don't think they can be changed easily. Their envctrl
driver is in OpenSolaris so it should be possible to hack it to do
whatever you like.

-Tobias