Hi, On Fri, Oct 16, 2020 at 6:09 AM Quentin Perret <qperret@xxxxxxxxxx> wrote: > > On Friday 16 Oct 2020 at 14:50:29 (+0200), Daniel Lezcano wrote: > > On 16/10/2020 14:18, Quentin Perret wrote: > > > On Friday 16 Oct 2020 at 13:48:33 (+0200), Daniel Lezcano wrote: > > >> If the SCMI is returning abstract numbers, the thermal IPA governor will > > >> use these numbers as a reference to mitigate the temperature at the > > >> specified sustainable power which is expressed in mW in the DT. So it > > >> does not work and we can not detect such conflict. > > >> > > >> That is why I'm advocating to keep mW for the energy model and make the > > >> SCMI and DT power numbers incompatible. > > > > > > I think it's fair to say SCMI-provided number should only be compared to > > > other SCMI-provided numbers, so +1 on that. But what I don't understand > > > is why specifying the EM in mW helps with that? > > > > It is already specified in mW. I'm just saying to not add the > > 'scale'/'abstract'/'bogoWatt' in the documentation. > > > > > Can we not let the providers specify the unit? > > > > Yes, it is possible but the provider must give the 'unit' and the energy > > model must store this information along with the "power" numbers, so we > > can compare apple with apple. > > > > Today, the energy model is using the mW unit only and the providers are > > not telling the 'unit', so both are missing. > > > > Because both are missing, it does not make sense to talk about > > 'abstract' values in the energy model documentation until the above is > > fixed. > > Right, so that sounds like a reasonable way forward with this series. > > Lukasz would you be able to re-spin this with a first patch that allows > the EM provider to specify a unit? And perhaps we could use Doug's idea > for the sustained power DT binding and allow specifying a unit > explicitly there too, so we're sure to compare apples with apples. The one issue that I started with, though, is that I wanted to be able to specify "sustainable-power" for a board in the device tree. Unless you think you'll convince Rob that it's OK to provide a "units" property in the device tree then just adding a "units" to the API won't help us because you'll still be stuck mixing/matching with a value based in mW, right? ...or are you suggesting that the board-specific value "sustainable-power" would also have to come from SCMI? That would be pretty annoying. -Doug
