History log of /drivers/cpufreq/e_powersaver.c
Revision Date Author Comments
fa8031aefec0cf7ea6c2387c93610d99d9659aa2 26-Jan-2012 Andi Kleen <ak@linux.intel.com> cpufreq: Add support for x86 cpuinfo auto loading v4

This marks all the x86 cpuinfo tables to the CPU specific device drivers,
to allow auto loading by udev. This should simplify the distribution
startup scripts for this greatly.

I didn't add MODULE_DEVICE_IDs to the centrino and p4-clockmod drivers,
because those probably shouldn't be auto loaded and the acpi driver
be used instead (not fully sure on that, would appreciate feedback)

The old nforce drivers autoload based on the PCI ID.

ACPI cpufreq is autoloaded in another patch.

v3: Autoload gx based on PCI IDs only. Remove cpu check (Dave Jones)
v4: Use newly introduce HW_PSTATE feature for powernow-k8 loading

Cc: Dave Jones <davej@redhat.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
826e570bb24de7671be66de7a6f036c304caad1e 24-Jul-2011 Rafał Bilski <rafalbilski@interia.pl> [CPUFREQ] e_powersaver: Allow user to lower maximum voltage

Add new module option "set_max_voltage".
One of the lessons learned from Adaptive Powersaver is that voltage values
returned by processor are for worst case scenario. But required voltage
is changing with CPU temperature. And even processors produced in the same
batch can have different minimum voltage necessary for stable work at
specified frequency.
On Elonex Webbook, once system starts, temperature never drops below
48 deg. C. Loading module after systems start allows user to lower CPU
voltage and still have stable system.
Sadly C7 doesn't allow code to set frequency or voltage from outside limits.
If you ask it to set voltage lower then minimum it will ignore you. Thats
why it isn't possible to change minimum voltage for minimum frequency too.
Changing maximum voltage on Elonex Webbook leads to very good results. Looks
like VIA C7 1.6GHz 1084mV can safetly run at 892mV. This means 83% of
orginal value. If same percentage applies to power generated it means 12.5W
in the place of 15W. Not much, but it is better then nothing.
Only C7-M makes it possible.
If voltage is too low by 16mV or more you will experience kernel panic.
If voltage is too low by 32mV or more you will experience system freeze.

Signed-off-by: Rafał Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
27e954c241673d2437448bd8bf0eaa7cd81a4b15 21-Jul-2011 Rafał Bilski <rafalbilski@interia.pl> [CPUFREQ] e_powersaver: Check BIOS limit for CPU frequency

Call ACPI function to get BIOS limit for CPU frequency.
Fail if processor would like to run at higher frequency.
Allow user to ignore BIOS limit.

eps: Detected VIA Model D C7-M
eps: Current voltage = 1084mV
eps: Current multiplier = 16
eps: Highest voltage = 1084mV
eps: Highest multiplier = 16
eps: Lowest voltage = 844mV
eps: Lowest multiplier = 4
eps: ACPI limit 1.60GHz

Signed-off-by: Rafał Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
ed361bf08033f165e0a004f254919e13f07df0ae 20-Jul-2011 Rafał Bilski <rafalbilski@interia.pl> [CPUFREQ] e_powersaver: Additional checks

Some systems are using 1,2Ghz@844mV processors running at 600MHz@796mV.
Try to detect such systems and don't touch anything on it. If CPU doesn't have
P-States in BIOS it should run at maximum frequency.
Allow user to bypass checks by means of two new options.
Don't set frequency to maximum on module unloading to avoid bada boom.
It is also possible that some processors may have incorrect values in min/max
registers caused by error in manufacturing process. Probably it would be BIOS
job to set them to right frequency and P-States tables would have correct
values inside.
Two additional sanity checks for voltage.

Signed-off-by: Rafał Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
bb0a56ecc4ba2a3db1b6ea6949c309886e3447d3 20-May-2011 Dave Jones <davej@redhat.com> [CPUFREQ] Move x86 drivers to drivers/cpufreq/

Signed-off-by: Dave Jones <davej@redhat.com>