On 6.12.2024 11:21 AM, Sudeep Holla wrote: > On Mon, Oct 28, 2024 at 03:22:57PM +0100, Konrad Dybcio wrote: >> From: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx> >> >> Certain firmware implementations (such as the ones found on Qualcomm >> SoCs between roughly 2015 and 2023) expose an S3-like S2RAM state >> through the CPU_SUSPEND call, as opposed to exposing PSCIv1.0's >> optional PSCI_SYSTEM_SUSPEND. >> > > If so, can you elaborate why s2idle doesn't work as an alternative to what > you are hacking up here. Please see other branches of this thread > >> This really doesn't work well with the model where we associate all >> calls to CPU_SUSPEND with cpuidle. Allow specifying a single special >> CPU_SUSPEND suspend parameter value that is to be treated just like >> SYSTEM_SUSPEND from the OS's point of view. >> >> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx> >> --- >> Documentation/devicetree/bindings/arm/psci.yaml | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/arm/psci.yaml b/Documentation/devicetree/bindings/arm/psci.yaml >> index cbb012e217ab80c1ca88e611e7acc06c6d56fad0..a6901878697c8e1ec1cbfed62298ae3bc58f2501 100644 >> --- a/Documentation/devicetree/bindings/arm/psci.yaml >> +++ b/Documentation/devicetree/bindings/arm/psci.yaml >> @@ -98,6 +98,12 @@ properties: >> [1] Kernel documentation - ARM idle states bindings >> Documentation/devicetree/bindings/cpu/idle-states.yaml >> >> + arm,psci-s2ram-param: >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + description: >> + power_state parameter denoting the S2RAM/S3-like system suspend state > > Yet another NACK as this corresponds to PSCI SYSTEM_SUSPEND and as per > specification it takes no such parameter. This is just misleading. > Yeah PSCI_SYSTEM_SUSPEND takes care of this on platforms that expose it. DEN0022F.b Section 6.5. recommends that CPU_SUSPEND StateID includes a field for system-level power down states. This binding change only adds a way for DT-based platforms to associate such state with S2RAM suspend. That may be a bit Linux-specific whereas bindings are supposed to be OS-agnostic, but since we effectively want one PSCI state for deep suspend regardless of the OS, I would think this kind of hint is fine. Konrad
