问题
I am trying to use cpu-frequency scaling to set cpu frequency. In my system, only powersave , performance frequency-scaling-governor supported. It was explained in other document, by default, intel_pstate is enabled and it only supports powersave , performance frequency-scaling-governor and solution is disable intel_pstate. So I tried to disable as below
sudo nano /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="intel_pstate=disable"
sudo update-grub
on reboot, intel_pstate is enabled.
so , again I made following changes in grub
sudo nano /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="intel_pstate=disable acpi=force"
sudo update-grub
on reboot, it still shows intel_pstate is enabled.
when I execute following command,
$ cpupower -c all frequency-info
analyzing CPU 7:
driver: intel_pstate
CPUs which run at the same hardware frequency: 7
CPUs which need to have their frequency coordinated by software: 7
maximum transition latency: Cannot determine or is not supported.
hardware limits: 1.60 GHz - 3.90 GHz
available cpufreq governors: performance powersave
current policy: frequency should be within 1.60 GHz and 3.90 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency: 1.72 GHz (asserted by call to hardware)
boost state support:
Supported: yes
Active: yes
25500 MHz max turbo 4 active cores
25500 MHz max turbo 3 active cores
25500 MHz max turbo 2 active cores
25500 MHz max turbo 1 active cores
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
intel_pstate
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
performance powersave
As userspace governor is not available, I am unable to use cpu-frequency scaling (cpupower ).
I am using Intel Core-i7 @3.40GHZ, Linux debian-8.0 (kernel- 3.16.35 ).
It will be a great help if you can help me to resolve this problem. Thank you in advance.
EDIT 1:
As per suggestion of Peter Cordes,I make manual entry during boot time and now intel_pstate is disabled, but no cpu frequency governor or acpi cpufrequency driver not activated.
root@debian:~# cpupower -c 0 frequency-info
analyzing CPU 0:
no or unknown cpufreq driver is active on this CPU
CPUs which run at the same hardware frequency: Not Available
CPUs which need to have their frequency coordinated by software: Not Available
maximum transition latency: Cannot determine or is not supported.
hardware limits: Not Available
available cpufreq governors: Not Available
Unable to determine current policy
current CPU frequency: Unable to call hardware
current CPU frequency: Unable to call to kernel
boost state support:
Supported: yes
Active: yes
25500 MHz max turbo 4 active cores
25500 MHz max turbo 3 active cores
25500 MHz max turbo 2 active cores
25500 MHz max turbo 1 active cores
As no cpu frequency governor available, I am not able to set cpu frequency. I got following error messages when I try to set cpu frequency.
root@debian:~# cpupower -c 0 frequency-set -f 2000000
Setting cpu: 0
Error setting new values. Common errors:
- Do you have proper administration rights? (super-user?)
- Is the governor you requested available and modprobed?
- Trying to set an invalid policy?
- Trying to set a specific frequency, but userspace governor is not available,
for example because of hardware which cannot be set to a specific frequency
or because the userspace governor isn't loaded?
回答1:
sorry to post this as an answer but I don't have the reputation to post as a comment :/
I had the same problem when trying to disable intel_pstate driver in my intel core i7. While managing to disable it, acpi-cpufreq was not loading properly, the problem being SpeedStep was disabled. SpeedStep allows the frequency to be changed by software in these microprocessors, with it disabled it can only be touched by the hardware. You can access this option through BIOS settings. I hope that helps!
来源：https://stackoverflow.com/questions/52477213/how-to-forcefully-disable-intel-pstate-intel-pstate-is-enabled-on-reboot-even-w