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path: root/drivers/cpufreq/e_powersaver.c
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2012-01-27cpufreq: Add support for x86 cpuinfo auto loading v4Andi Kleen1-9/+11
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>
2011-10-27[CPUFREQ] e_powersaver: Allow user to lower maximum voltageRafał Bilski1-0/+18
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>
2011-10-27[CPUFREQ] e_powersaver: Check BIOS limit for CPU frequencyRafał Bilski1-0/+76
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>
2011-10-27[CPUFREQ] e_powersaver: Additional checksRafał Bilski1-11/+30
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>
2011-05-20[CPUFREQ] Move x86 drivers to drivers/cpufreq/Dave Jones1-0/+367
Signed-off-by: Dave Jones <davej@redhat.com>