[Buildroot] cpufreq: cpufreq_online: CPU0: Running at unlisted freq

[Andy Bergh]

This problem has been resolved.

The cause was the use of the SYSBOOT pins (GPIO0_10 and GPIO0_11) which are
used to set the frequency on the chip:

[image: image.png]

The pins were electronically isolated and configured to be used only after
the boot register had been loaded and the OS started.
This 'isolation' was not optimal which then caused this intermittent
startup 'unlisted freq' message/error.

Simply properly isolating the pins solved it. Hopefully this solution may
help anyone in the future.

Regards

On Wed, May 31, 2023 at 4:08 PM Andy Bergh <allmyaddmin at gmail.com> wrote:

> Hi,
>
> I was not able to access the mailing list to search for this topic, I hope
> I am not repeating the question.
>
> I am running a custom OS for the Beaglebone Black and am using the serial
> port to talk to an external LCD screen via UART1.
> This works most of the time at startup, but about 15% after powering on
> the board the LCD does not work. It looks like the BAUD
> rate on my OS is slightly off.
>
> After having a look at the console startup log I noticed that only on a
> failure do the following messages appear:
> ...
> Calibrating delay loop... *915.86* BogoMIPS (lpj=4579328) *// On a
> normal/working startup the output is: 996.14 BogoMIPS (lpj=4980736)*
> ...
> [4.214981] cpufreq: cpufreq_online: CPU0: Running at unlisted freq: 923076
> KHz
> [4.450726] cpufreq: cpufreq_online: CPU0: Unlisted initial frequency
> changed to: 1000000 KHz
> ...
> I have searched extensively on the internet but could not resolve the
> issue.
> Based on what I read I also double checked the blob/*.dts files and
> everything seems in order. I used this link
> <https://software-dl.ti.com/processor-sdk-linux/esd/docs/06_03_00_106/AM335X/linux/Foundational_Components/Kernel/Kernel_Drivers/Power_Management.html#power-management>
> to verify my setup.
>
> Would anyone be able to point me in the right direction regarding this
> issue? How can I resolve this "*Running at unlisted freq*" warning?
> Any information would be much appreciated. I am at a loss here.
>
> Thank you and regards
> Andy
>
>
>
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