This proposal has been accepted as a session.


One Line Summary

ACPI vs Device Tree - Moving Forward: Discussion on device enumeration methods


As Matthew Garrett said in an LKML post:

ACPI and DT overlap in that they both provide a mechanism for enumerating non-enumerable devices, and both also provide a mechanism for attaching additional configuration data to devices (which may or may not be otherwise enumerable). There’s a sufficient overlap in functionality that at least one platform that’s traditionally been Device Tree (ARM) is also adding support for ACPI – there’s even ACPI-based ARM hardware on the market already.

Right now that’s a problem for us. The same hardware may end up shipped with either ACPI or DT-based firmware, and at the moment we’d need to either write two drivers or one driver with two glue layers. This is somewhat suboptimal."

Moreover, some systems are shipped with ACPI firmware whose ACPI tables do not contain all information necessary to enumerate and handle all devices, but at least in some cases there are known DT bindings for the hardware in question that could be used for this purpose.

We are going to discuss those problems and try to reach an agreement on the way to resolve them.


ACPI, Device Trees, Flattened Device Trees, DT, FDT, device enumeration


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