I wondered if anyone got CPU scaling working, the Omnia is at max cpu-frequency all the time and never scales down to a resonable speed, which could save a lot of power.
But the kernel which nic.cz built has no module for it (at least as far as I can see) and so it is not possible to usw an ondemand or powersave govenor…
Has anyone gotten the scaling to work or tried it at least?
Well that’s question I have also. One thread solved here how to cool chip better by enhanced passive cooling. but from my point of view its not correct way. Correct is to have flexible power-management and possibility to underclock CPU on demand.
Would be interesting feature, I guess chipset in turris supports it.
edit: actually, the patches are applying quite well, only one little fix is needed - i’m currently testing stabilty with the patches, but looks good atm
Problem is, that it is considered unstable/dangerous feature and it didn’t reduce the overall power and thermal profile so much, to justify testing and stabilization effort needed in order to put it into mainline or/and TurrisOS. If somebody have time to test it extensively and possibly cleanup the work, I will be glad to re-send Gregory’s patches along with my fixes.
Another story is CPU idle support, which is also missing and it seems to be result of a HW bug somewhere in I/O subsystem and that has been temporarily resolved (quite a long time ago) by disabling the CPU idle in this patch https://patchwork.kernel.org/patch/6319581/ . We are investigating this issue in cooperation with Marvell, however I can’t make any guarantees or even assumptions o when or if ever it is going to be resolved without disabling the driver.
However it seems that even with CPU idle and with on-demand cpufreq driver it won’t make that big difference. Our experiments indicate that the difference between full power 1600MHz with 100% CPU utilization and idle at 800MHz was only 1-1.5 watts.
actually, no, the fix was a renamed function… interestingly the patch series from Gregory seems to work OOTB for me - at least i can see it switching between 800 and 1600 MHz and if i put the box under load and switch to 800MHz manually there’s a big temperature drop
thanks for hints. On default configuration (min 800, max 1600, governor performance, driver cpufreq-dt) Ive got 0 transitions, running on 1600 all the time
thanks, it looks like working now Although I didnt observe much temp affect either, so at least on “paper” it works. Dunno if there isnt some other issue under.