Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/36864 )
Change subject: soc/intel/cannonlake: Add chip config to override CPU flex ratio ......................................................................
Patch Set 9:
Patch Set 9:
Patch Set 9:
Patch Set 9:
I would still like to have a detailed documentation of the UPD. It's still unclear to me how the system is affected after boot, as there is also `BootFrequency` which seems independent from this.
I guess you can refer to BWG chapter 11 title power management
Which BWG, document number please.
Its SKL CPU BWG (we have two BWG, one for CPU and another for PCH). doc 33391
Thanks. Alas, I can't find it. It might need a different level of access. But it's good to know that more documentation exists.
I was looking mostly at 550049, but realized by now that it doesn't say "BWG" but "BIOS Specification".
That doesn't have power management chapter ?
Is this another document beside the "BIOS Specification"? I often confuse the two. Does your BWG only document the hardware or FSP too? Because in all the hardware documentation it says "Flex Ratio" and in FSP it says "CpuRatio". Please, where is it documented that that two mean the very same thing?
I guess its discrepancy in name which we can raise a request to fix, i will take a note. Its both same as you can read the help text from FSP-M header.
I must be looking at a different header. Mine just says: 0-63 and 0 is disabled. Nothing about Flex Ratio, reboots, changed TSC, etc.
yes, its same and i will pass this feedback to improve the help text and name going forward