On Tue, Oct 02, 2018 at 11:56:56AM -0700, Saravana Kannan wrote: > > On 10/02/2018 04:17 AM, Sudeep Holla wrote: [...] > > Yes, I do understand I have made the same point multiple time and it's > > intentional. We need to get the fragmented f/w support story fixed. > > Different ARM vendors are doing different things in f/w and ARM sees the > > same fragmentation story as before. We have come up with new specification > > and my annoying multiple emails are just to constantly remind the same. > > > > I do understand we have existing implementations to consider, but fixing > > the functionality in arbitrary way is not a good design and it better > > to get them fixed for future. > > I believe the fragmentation you are referring to is in the > interface/communication protocol. I see the benefit of standardizing that as > long as the standard actually turns out to be good. But that's completely > separate from what the FW can/can't do. Asking to standardize what the FW > can/can't do doesn't seem realistic as each chip vendor will have different > priorities - power, performance, cost, chip area, etc. It's the conflation > of these separate topics that doesn't help IMHO. I agree on interface/communication protocol fragmentation and firmware can implement whatever the vendor wish. What I was also referring was the mix-n-match approach which should be avoided. e.g. Device A and B's PM is managed completely by firmware using OSPM hints Suppose Device X's PM is dependent on Device A and B, in which case it's simpler and cleaner to leave Device X PM to firmware. Reading the state of A and B and using that as hint for X is just overhead which firmware can manage better. That was my main concern here: A=CPU and B=some other device and X is inter-connect to which A and B are connected. If CPU OPPs are obtained from f/w and this inter-connect from DT, mapping then is a mess and that's what I was concerned. I am sorry if that's not the scenario here, I may have mistaken then. -- Regards, Sudeep
