On 20.12.2024 2:55 PM, Sudeep Holla wrote: > On Fri, Dec 20, 2024 at 01:54:45PM +0100, Konrad Dybcio wrote: >> On 20.12.2024 12:27 PM, Sudeep Holla wrote: >>> On Thu, Dec 19, 2024 at 08:43:27PM +0100, Konrad Dybcio wrote: >>>> 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. >>>> >>> >>> And those that don't advertise/expose don't get to use, simple. >> >> The spec says: >> >> "The call is equivalent to using the CPU_SUSPEND call for the >> deepest possible platform powerdown state." >> > > Please take a look at the preconditions for both the calls. They are > different. Which is *precisely* why I want to tell the OS that it's a S2RAM state, so that different actions can be taken in peripheral device drivers. Konrad
