Bug 6699

Summary:	Possible Frequencies steps changed with kernel upgrade in p4-clockmod
Product:	Power Management	Reporter:	Torsten Krah (krah.tm)
Component:	cpufreq	Assignee:	Dominik Brodowski (linux)
Status:	CLOSED INVALID
Severity:	normal
Priority:	P2
Hardware:	i386
OS:	Linux
Kernel Version:	2.6.16.20	Subsystem:
Regression:	---	Bisected commit-id:

Description Torsten Krah 2006-06-16 09:48:27 UTC

Most recent kernel where this bug did not occur: 2.6.15.6
Distribution: Debian Sarge
Hardware Environment: Dell Power Edge 1600SC with 2800 GHz P4 Xeon HT
Software Environment:
Problem Description: Using the new kernel, cpufreq-info only shows:

hardware limits: 2.10 GHz - 2.80 GHz
available frequency steps: 2.10 GHz, 2.45 GHz, 2.80 GHz

With the 2.6.15 version it shows much more:

hardware limits: 350 MHz - 2.80 GHz
available frequency steps: 350 MHz, 700 MHz, 1.05 GHz, 1.40 GHz, 1.75 GHz, 2.10
GHz, 2.45 GHz, 2.80 GHz

Steps to reproduce: Boot with 2.6.16.20 Kernel and watch cpufreq-info output.

kind regards

Torsten

Comment 1 Dominik Brodowski 2006-06-22 11:02:58 UTC

A hardware bug makes it risky to use throttling states with frequencies lower
than 2.0 GHz on this processor.

Comment 2 Torsten Krah 2006-06-22 11:50:23 UTC

Would have been nice to read about such changes in Changelog of Kernel, maybe i
missed it but afaik i read nothing about.
What are you meaning with risky? Any documentation about this Bug out there, can
you link something or explain maybe. thx.

kind regards

Torsten

Comment 3 Dominik Brodowski 2006-06-22 12:04:29 UTC

http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=c70ca00f77eb1bb69c5a2d029b3a911bc88eac1b

is the change, and "N60" refers to the errata noted in Intel's documentation
spec sheet at http://developer.intel.com/design/pentium4/specupdt/249199.htm