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

Stephen Boyd
2021-08-21T18:17:41Z

Quoting Sibi Sankar (2021-08-20 07:24:02)
> 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.
>

Alright. Is that reflected somewhere in the commit text? I must have
missed it. Can you please add it?