Hi Marcel,
We just want to have DVFS support for our Colibri T30s in Yocto Linux. We know the T30 is going EOL but we just want to use up our existing stock of T30s before possibly moving to another Toradex module.
Can you please give us advice on the Device Tree entries needed to enable DVFS for the T30?
BSP 2.8.8
Yocto, Rocko but modified to compile the 6.1 Kernel
Brad
If you can’t tell us this, could you at least point us to a resource that explains the target voltages for the T3 based on different clock cycles? We tried to find the info in the Nvidia Technical Reference Manual to no avail.
You would likely need to include the following two dtsi files:
Please note that we never tested DVFS using the Linux 6.1 kernel.
Thanks Marcel, that at least seemed to load tegra20-cpufreq and produced the following output.
[ 3.046334] tegra20-cpufreq tegra20-cpufreq: hardware version 0x8 0x1
[ 3.054707] cpufreq: cpufreq_online: CPU0: Running at unlisted initial frequency: 600000 KHz, changing to: 640000 KHz
But unfortunately we still the same power consumption even though we I have tried to manually set the cpufreq … power consumption is steady at 5 Watts even though I have tried to change the cpu frequency with cpufreq-set to very different values. Should I recompile the kernel with DEBUG_FS set and see if I can see more info? cpufreq-set and cpufreq-info don’t seem to be working.
We understand that you not tested this functionality, but what would do in our place. We want Linux on the T30 modules that we still have in stock (before we switch to a new module ) and we need obviously need DVFS to save power… should we go back to last mainline kernel recipes that you guys have on your github repo and try to patch the 5.x kernel for DVFS?
should we go back to last mainline kernel recipes that you guys have on your github repo and try to patch the 5.x kernel for DVFS?
As mentioned before we really never ever had any validated mainline-based BSP for the Apalis/Colibri T20/T30. So we really do not have any readily available answers to any of your questions. One would basically need to integrate such DVFS functionality upstream first. It might just be missing some frequency configuration or memory timings. We really do not know, sorry.