Re: [PATCH v2 00/12] coresight: Add CPU cluster funnel/replicator/tmc support

Sudeep Holla
2025-12-18T11:33:12Z

On Thu, Dec 18, 2025 at 12:09:40AM -0800, Yuanfang Zhang wrote:
> This patch series adds support for CoreSight components local to CPU clusters,
> including funnel, replicator, and TMC, which reside within CPU cluster power
> domains. These components require special handling due to power domain
> constraints.
>

Could you clarify why PSCI-based power domains associated with clusters in
domain-idle-states cannot address these requirements, given that PSCI CPU-idle
OSI mode was originally intended to support them? My understanding of this
patch series is that OSI mode is unable to do so, which, if accurate, appears
to be a flaw that should be corrected.

> Unlike system-level CoreSight devices, these components share the CPU cluster's
> power domain. When the cluster enters low-power mode (LPM), their registers
> become inaccessible. Notably, `pm_runtime_get` alone cannot bring the cluster
> out of LPM, making standard register access unreliable.
>

Are these devices the only ones on the system that are uniquely bound to
cluster-level power domains? If not, what additional devices share this
dependency so that we can understand how they are managed in comparison?

> To address this, the series introduces:
> - Identifying cluster-bound devices via a new `qcom,cpu-bound-components`
> device tree property.

Really, no please.

--
Regards,
Sudeep