On Tue 27 Jul 02:35 CDT 2021, Rajendra Nayak wrote: > > On 7/25/2021 10:31 PM, Bjorn Andersson wrote: > > On Mon 19 Jul 23:29 CDT 2021, Rajendra Nayak wrote: > > > > > > > > > > > On 7/20/2021 12:49 AM, Bjorn Andersson wrote: > > > > On Mon 19 Jul 04:37 CDT 2021, Rajendra Nayak wrote: > > > > > > > > > > > > > > > > > > > On 7/17/2021 3:29 AM, Bjorn Andersson wrote: > > > > > > On Fri 16 Jul 16:49 CDT 2021, Stephen Boyd wrote: > > > > > > > > > > > > > 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. > > > > > > > > > > what rail is this? the mmcx? Perhaps it does not support RET. > > > > > cx usually supports both collapse state and RET. > > > > > > > > > > > > > That was the one I was specifically looking at for the MDSS_GDSC->MMCX > > > > issue, so it's likely I didn't look elsewhere. > > > > > > > > > > > > > > > > > > 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. > > > > > > > > > > > > > > > > > > > But if that's the case, I don't think it's appropriate for the "enabled > > > > > > state" of the domain to use any of those corners. > > > > > > > > > > I rechecked the downstream kernels where all this voting happens from within > > > > > the clock drivers, and I do see votes to min_svs for some clocks, but Stephen is > > > > > right that RET is not something that's voted on while in active state. > > > > > > > > > > But always going with something just above the ret level while active will also > > > > > not work for all devices, for instance for i2c on 7180, it needs a cx vote of > > > > > low svs while the rail (cx) does support something lower than that which is min svs. > > > > > (why can't it just work with min svs?, I don't know, these values and recommendations > > > > > come in from the voltage plans published by HW teams for every SoC and we just end up > > > > > using them in SW, perhaps something to dig further and understand which I will try and > > > > > do but these are the values in voltage plans and downstream kernels which work for now) > > > > > > > > > > > > > So to some degree this invalidates my argumentation about the > > > > enabled_corner in rpmhpd, given that "enabled" means a different corner > > > > for each rail - not just the one with lowest non-zero value. > > > > > > Right, it might work in some cases but might not work for all. > > > > > > > Which makes it way less desirable. > > > > The enable state for rpmhpd power domains doesn't meet my expectations > > for how a power domain should behave, > > Right and that's perhaps because these are not the usual power-domains, > which have one "on/active" state and one or more "off/inactive" states (off/ret/clock-stop) > Rpmhpd has multiple "on/active" states, and whats "on/active" for one consumer > might not be "on/active" for another, so this information is hard to be managed > at a generic level and these requests in some way or the other need to come > in explicitly from the resp. consumers. > I think it's fine if we just acknowledge that this is how the rpmhpd domains works. But I am worried about how we're going to handle the case where the consumer is indirectly referencing one of these power-domains using a subdomain (gdsc). And the open question is if a solution to that problem will solve this problem as well, or if we need to have this and some mechanism to describe the "on state" for the parent of a subdomain. Regards, Bjorn
