Re: [PATCH v5 02/13] dt-bindings: remoteproc: qcom: pas: Add QMP property

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On 2021-08-20 00:25, Stephen Boyd wrote:
Quoting Sibi Sankar (2021-08-18 20:02:05)
The load state power-domain, used by the co-processors to notify the
Always on Subsystem (AOSS) that a particular co-processor is up/down,
suffers from the side-effect of changing states during suspend/resume.
However the co-processors enter low-power modes independent to that of
the application processor and their states are expected to remain
unaltered across system suspend/resume cycles. To achieve this behavior
let's drop the load state power-domain and replace them with the qmp
property for all SoCs supporting low power mode signalling.


How do we drop the load state property without breaking existing DTBs?
Maybe we need to leave it there and then somehow make it optional? Or do
we not care about this problem as the driver will start ignoring it?

We can afford to break the bindings
because of the following reason:

* Load state in mainline is currently
  broken i.e. it doesn't serve its
  main purpose of signalling AOP of
  the correct state of Q6 during
  system suspend/resume. Thus we
  can maintain current functionality
  even without the load state votes
  i.e. when a new kernel with load
  state removed is used with an older
  dtb the remoteproc functionality
  will remain the same.


--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.



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