Re: [PATCH v6 3/9] cxl/region: Skip decoder reset on detach for autodiscovered regions

Dan Williams
2026-03-12T19:54:06Z

Dan Williams wrote:
[..]
> All of this wants some documentation to tell users that the rule is
> "Hey, after any endpoint decoder has been seen by the CXL core, if you
> remove that endpoint decoder by removing or disabling any of cxl_acpi,
> cxl_mem, or cxl_port the CXL core *will* violently destroy the decode
> configuration". Then think about whether this needs a way to specify
> "skip decoder teardown" to disambiguate "the decoder is disappearing
> logically, but not physically, keep its configuration". That allows
> turning any manual configuration into an auto-configuration and has an
> explicit rule for all regions rather than the current "auto regions are
> special" policy.

Do not worry about this paragraph of feedback. I will start a new patch
set to address this issue. It is the same problem impacting the
accelerator series where driver reload resets the decode configuration
by default. Both accelerator drivers and userspace should be able to
opt-out / opt-in to that behavior.

This will want some indication that the root decoder space is designated
such that it does not get reassigned while the driver is detached.