Messages in this thread | | | Subject | Re: [PATCH v1 3/5] dt-bindings: arm: Add cpu-idle-states to Tegra194 CPU nodes | From | Sowjanya Komatineni <> | Date | Wed, 10 Mar 2021 15:19:35 -0800 |
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On 3/8/21 10:32 AM, Sowjanya Komatineni wrote: > > On 3/7/21 8:37 PM, Sudeep Holla wrote: >> On Wed, Mar 03, 2021 at 10:08:10PM -0800, Sowjanya Komatineni wrote: >>> This patch adds cpu-idle-states and corresponding state nodes to >>> Tegra194 CPU in dt-binding document >>> >> I see that this platform has PSCI support. Can you care to explain why >> you need additional DT bindings and driver for PSCI based CPU suspend. >> Until the reasons are convincing, consider NACK from my side for this >> driver and DT bindings. You should be really using those bindings and >> the driver may be with minor changes there. >> > MCE firmware is in charge of state transition for Tegra194 carmel CPUs. > > For run-time state transitions, need to provide state request along > with its residency time to MCE firmware which is running in the > background. > > State min residency is updated into power_state value along with state > id that is passed to psci_cpu_suspend_enter > > Also states cross-over idle times need to be provided to MCE firmware. > > MCE firmware decides on state transition based on these inputs along > with its background work load. > > So, Tegra specific CPU idle driver is required mainly to provide > cross-over thresholds from DT and run time idle state information to > MCE firmware through Tegra MCE communication APIs. > > Allowing cross-over threshold through DT allows users to vary idle > time thresholds for state transitions based on different use-cases. > Hi Sudeep,
Can you please let me know if you have any more concerns for having this Tegra specific cpuidle driver?
Thanks
Sowjanya
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