p4tcc.c from FreeBSD

Nate Lawson nate at root.org
Sun Jul 25 21:02:25 PDT 2004

YONETANI Tomokazu wrote:
[CC on Nate Lawson hoping we can hear good news from him]
On Sun, Jul 25, 2004 at 11:50:52AM +0000, Johannes Hofmann wrote:
This patch adds Pentium 4 Thermal Control Circuit (TCC) support from
FreeBSD (originally from OpenBSD, I think). 
It can be used to reduce the CPU speed without ACPI support and might be
useful on machines where ACPI has problems.
In my tests it actually slowed things down, but I have no results about
battery life yet.
Thanks for the patch, but the last time this came up, we were going
to wait for the cpufreq driver to be committed to FreeBSD, IIRC. I'm not
sure about the detail of the cpufreq driver, but I hope it include
support for Enhanced SpeedStep Technology(EST) on Pentium M processors,
which is already implemented in NetBSD:

Of course this does not mean I'm against p4tcc.c driver to go into
DragonFly tree as it's already been used in FreeBSD.
I'm still working on the cpufreq framework.  When it goes in, it will 
probably have support for P4-M SS, ICH SS, ACPI throttling, and ACPI Px 
states.  I will probably be committing it after the 5.3-RELEASE due to 
the need to focus on addressing other problems people are having with 
ACPI (pci irq routing) before the release.

When I bring it in, I will convert p4tcc and the longrun drivers to 
cpufreq as well.  If you want to import your driver before then, I don't 
see a problem.


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