cpufreq and changing driver

Marco Calviani marco.calviani at gmail.com
Wed Nov 30 20:06:02 GMT 2005

Hi Nate,

2005/11/30, Nate Lawson <nate at root.org>:

> You should send the full output of "sysctl dev.cpu".  There is no
> cpufreq driver (est, acpi_perf, or other) driver running.  Perhaps look
> at your dmesg to see if one is probing/attaching.

> sysctl dev.cpu
dev.cpu.0.%desc: ACPI CPU
dev.cpu.0.%driver: cpu
dev.cpu.0.%location: handle=\_PR_.CPU0
dev.cpu.0.%pnpinfo: _HID=none _UID=0
dev.cpu.0.%parent: acpi0
dev.cpu.0.freq: 1000
dev.cpu.0.freq_levels: 1800/24000 1600/20000 1400/18000 1225/15750
1050/13500 1000/16000 875/14000 750/12000 625/10000 600/12000
525/10500 450/9000 375/7500 300/6000 225/4500 150/3000 75/1500

and if useful,

> dmesg | grep -i acpi
acpi0: <ACER TM8000> on motherboard
acpi0: Power Button (fixed)
pci_link0: <ACPI PCI Link LNKA> irq 6 on acpi0
pci_link1: <ACPI PCI Link LNKB> irq 10 on acpi0
pci_link2: <ACPI PCI Link LNKC> irq 6 on acpi0
pci_link3: <ACPI PCI Link LNKD> irq 6 on acpi0
pci_link4: <ACPI PCI Link LNKE> irq 10 on acpi0
pci_link5: <ACPI PCI Link LNKF> irq 0 on acpi0
pci_link6: <ACPI PCI Link LNKG> irq 0 on acpi0
pci_link7: <ACPI PCI Link LNKH> irq 10 on acpi0
acpi_ec0: <Embedded Controller: GPE 0x1d> port 0x62,0x66 on acpi0
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x1008-0x100b on acpi0
cpu0: <ACPI CPU> on acpi0
acpi_perf0: <ACPI CPU Frequency Control> on cpu0
pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
pci0: <ACPI PCI bus> on pcib0
pcib1: <ACPI PCI-PCI bridge> at device 1.0 on pci0
pci1: <ACPI PCI bus> on pcib1
pcib2: <ACPI PCI-PCI bridge> at device 30.0 on pci0
pci2: <ACPI PCI bus> on pcib2
acpi_lid0: <Control Method Lid Switch> on acpi0
acpi_acad0: <AC Adapter> on acpi0
battery0: <ACPI Control Method Battery> on acpi0
battery1: <ACPI Control Method Battery> on acpi0
acpi_button0: <Sleep Button> on acpi0
acpi_tz0: <Thermal Zone> on acpi0
atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0
ppc0: <ECP parallel printer port> port 0x378-0x37f,0x778-0x77f irq 7
drq 3 on acpi0
sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
sio1 port 0x2f8-0x2ff irq 3 drq 1 on acpi0

> If you are using acpi and load cpufreq.ko, you've got all the cpufreq
> drivers in one package.  The right one for your platform will
> automatically probe/attach.

It seems that my system has recognized acpi_perf as the appropriate
driver. But since my CPU is a dothan type centrino i would like to
understand why is not possible to use the est driver.

> I have no idea what you mean by "on-demand governor".  The only
> automated control of cpu speed is either by the BIOS (which we can't
> control) or the TM/TM2 (and that one is heat-based, not load-based).

I was referring to this
http://www.intel.com/cd/ids/developer/asmo-na/eng/195910.htm?prn=Y and
http://lwn.net/Articles/55589/ introduced in linux kernel 2.6.9  .
Just to remind: sorry if this is not applicable to the freeBSD kernel.

In the linux case the system is much more responsive to actual user
actions in respect to what i'm experiencing with powerd. If i can help
in some way in testing i would like to contribute.

> --
> Nate


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