Quoting Bjorn Andersson (2021-07-16 13:52:12) > On Fri 16 Jul 15:21 CDT 2021, Stephen Boyd wrote: > > > Quoting Bjorn Andersson (2021-07-16 13:18:56) > > > On Fri 16 Jul 05:00 CDT 2021, Rajendra Nayak wrote: > > > > > > > qup-i2c devices on sc7180 are clocked with a fixed clock (19.2 MHz) > > > > Though qup-i2c does not support DVFS, it still needs to vote for a > > > > performance state on 'CX' to satisfy the 19.2 Mhz clock frequency > > > > requirement. > > > > > > > > > > Sounds good, but... > > > > > > > Use 'required-opps' to pass this information from > > > > device tree, and also add the power-domains property to specify > > > > the CX power-domain. > > > > > > > > > > ..is the required-opps really needed with my rpmhpd patch in place? > > > > > > > Yes? Because rpmhpd_opp_low_svs is not the lowest performance state for > > CX. > > On e.g. sm8250 the first available non-zero corner presented in cmd-db > is low_svs. Indeed. On sc7180 it's not the first non-zero corner. I suppose retention for CX isn't actually used when the SoC is awake so your rpmhpd patch is putting in a vote for something that doesn't do anything at runtime for CX? I imagine that rpmh only sets the aggregate corner to retention when the whole SoC is suspended/sleeping, otherwise things wouldn't go very well. Similarly, min_svs may be VDD minimization? If so, those first two states are basically states that shouldn't be used at runtime, almost like sleep states. > > And if this (which?) clock requires a higher corner than the lowest > possible in order to tick at this "lowest" frequency, I'm certainly > interested in some more details. >
