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

[Sibi Sankar]

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.


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