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  • Re: Raspberry Pi 1B cpu scaling

    From Diederik de Haas@21:1/5 to ARM on Fri Nov 11 11:33:57 2022
    Copy: mailinglist@unix-solution.de (basti)

    On Friday, 11 November 2022 10:25:58 CET basti wrote:
    I have installed the 20220121_raspi_1_bullseye.img.xz image from https://raspi.debian.net/tested-images/
    on one of my old Raspberry Pi 1B.

    As I can see cpu scaling seems to not work.

    Support for CPU frequency scaling on the RPi 0/1 got added [1] to the 5.14.12-2~exp1 (and later) kernel and is not available on a Bullseye system. You can get it by installing a kernel via backports or upgrading to Bookworm/ Testing.

    /sys/devices/system/cpu/cpu/X//cpufreq/scaling_max_freq is not available
    so I compile vcgencmd to test it.

    |root@counter:~# vcgencmd measure_clock arm
    frequency(48)=700000000

    Is always 700 Mhz, also

    AFAIK, the RPi 1 only has 1 frequency: 700Mhz ...

    when I try to stress the Pi with "stress --cpu 2 --timeout 60s".

    and only 1 CPU core, so I don't expect any change in that.

    The RPi 0 (Zero) uses the same kernel and does have multiple frequencies.

    HTH

    [1] https://salsa.debian.org/kernel-team/linux/-/merge_requests/381
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  • From basti@21:1/5 to All on Fri Nov 11 11:20:01 2022
    Hello,

    I have installed the 20220121_raspi_1_bullseye.img.xz image from https://raspi.debian.net/tested-images/
    on one of my old Raspberry Pi 1B.

    As I can see cpu scaling seems to not work.

    |I have to load the kernel model.

    root@counter:~# lsmod | grep cpu
    cpufreq_ondemand       16384  0

    /sys/devices/system/cpu/cpu/X//cpufreq/scaling_max_freq is not available
    so I compile vcgencmd to test it.

    |root@counter:~# vcgencmd measure_clock arm
    frequency(48)=700000000

    Is always 700 Mhz, also when I try to stress the Pi with "stress --cpu 2 --timeout 60s".

    root@counter:~# vcgencmd get_config int | grep freq
    arm_freq=950
    arm_freq_min=700
    core_freq=250
    sdram_freq=450
    hdmi_pixel_freq_limit:0=0x9a7ec80

    So the next step I have try is to increase arm_freq_min to 800.
    After reboot
    root@counter:~# vcgencmd measure_clock arm
    frequency(48)=800000000

    So I verify that vcgencmd show the correct value.

    Can someone reproduce this?
    Why did cpu scaling not work on pi1 ?

    Best Regards

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