On Thu, Oct 21, 2021 at 03:13:30PM +0200, Ulf Hansson wrote: > On Wed, 20 Oct 2021 at 14:11, Rob Herring <robh@xxxxxxxxxx> wrote: > > [...] > > 'power domains' in DT is supposed to mean physical power islands in > > the h/w where as genpd can be whatever you want. Are power and > > performance domains always 1:1? > > I wouldn't say that "power domains" *must* correspond to physical > power islands. At least, that's not the way the bindings are being > used. For example, if it makes better sense to keep some of the logic > in FW, rather than describing a complete topology in DT, that should > be perfectly fine. > I agree. The DT must either have h/w view or f/w view of the topology and not both(that is inviting more trouble in terms of bindings as well as handling it in the OSPM). > Additionally, I am not suggesting that "performance domains" and > "power domains" must map 1:1. A device can be performance managed > through one domain and power managed by another, that would be > perfectly fine to me. I don't understand what you mean by that. Do you expect to create a genpd with no power domain ops and just performance ops to deal with scenario I have been presenting(i.e. power domains for a set of devices(CPUs in particular) aren't exposed to OSPM while performance domains are). I really don't like to create psuedo/dummy power domains with no useful info(as f/w hides or abstracts it) just to represent the performance domains. Also with CPUs you can imagine all sort of combinations like: 1. cluster level perf domain + cpu level power domains 3. cluster level perf domain + cluster level power domains 2. cpu level perf domain + cpu level power domains 4. cpu level perf domain + cluster level power domains + power domains not available to OSPM in all the 4 combo. So I am really struggling to visualise a way to represent these based on your suggestion. -- Regards, Sudeep
