On 21-11-24 17:09:03, Dan Williams wrote: > On Fri, Nov 19, 2021 at 4:03 PM Ben Widawsky <ben.widawsky@xxxxxxxxx> wrote: > > > > The description of the CXL topology will be conveyed by a platform > > specific entity that is expected to be a singleton. For ACPI based > > systems, this is ACPI0017. When the topology host goes away, which as of > > now can only be triggered by module unload, it is desirable to have the > > entire topology cleaned up. Regular devm unwinding handles most > > situations already, but what's missing is the ability to teardown the > > root port. Since the root port is platform specific, the core needs a > > set of APIs to allow platform specific drivers to register their root > > ports. With that, all the automatic teardown can occur. > > Wait, no, that was one of the original motivations, but then we > discussed here [1] that devm teardown of a topology can happen > naturally / hierarchically. > > [1]: https://lore.kernel.org/r/CAPcyv4ikVFFqyfH2zLhBVJ28N1_gufGHd2gVbP2h+Rv2cZEpeA@xxxxxxxxxxxxxx > > No, the reason for the cxl_topology_host is as a constraint for when > CXL.mem connectivity can be verified from root to endpoint. Given that > endpoints can attach at any point in time relative to when the root > arrives CXL.mem connectivity needs to be revalidated at every topology > host arrival / depart event. Oops. I forgot to update the commit message, I will take what you wrote with slight modification.
