Messages in this thread | | | Subject | Re: [PATCH] ACPI / GED: use late init to allow other drivers init | From | Sinan Kaya <> | Date | Thu, 11 May 2017 09:43:14 -0400 |
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Hi Rafael,
On 5/10/2017 8:46 PM, Rafael J. Wysocki wrote: >> My proposal was to require platform AML code to indicate the dependencies >> between GED and drivers on the right side of the picture via _DEP as this >> cannot be done via normal kernel mechanisms. > Something like _DEP would be needed. > > However, _DEP as specified is only about operation region dependencies, which > doesn't seem to be applicable here. > > That said, _DEP is used for general dependecies by firmware already, but it > would at least be good to send a proposal for a spec update regarding that > before mandating using _DEP for GED.
OK. I'll reach out to Harb and let's see where the proposal goes.
> >> This approach might work in general. However, it also has its own caveats. >> >> All of these drivers on the right side are unrelated to each other. Some >> operating system can implement a subset of these drivers. >> >> If I include the dependencies, GED will never load for partial driver situations. >> This is also a deal breaker. > _DEP doesn't mean a hard dependency AFAICS. It is about ordering, not about > presence, at least as specified currently. > >> Why would you break some other feature if your OS doesn't support RAS as an >> example? >> >> Given all these lose bindings and no driver association, where do we go >> from here? >> >> I consider GED as a light version of Embedded controller (EC) implementation. > No, it is not.
Thanks for correction. Let me repeat with the correct terminology this time.
Don't we have the same problem on GPE/SCI mechanism?
An event that SCI is delivering may not be handled because the handler of the event is not present during OS boot?
The SCI relationship would be:
| SCI | <---> | Platform specific ACPI AML (_AEI) | <----> Vendor XYZ driver <----> Vendor I2C <----> ACPI GHES
> > It is more of a generalization of the GPE/SCI mechanism in order to make it > possible to cover things different from GPIO (which already is covered by > _AEI). > >> How is this problem solved for EC as it has the same problem? > It doesn't. The EC relies on the GPE/SCI mechanism to be there and that is > always present. > > Thanks, > Rafael
-- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
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