[PATCH v7] cpuidle, ACPI: Evaluate LPI arch_flags for broadcast timer

Sudeep Holla sudeep.holla at arm.com
Mon Sep 18 03:52:21 PDT 2023


On Fri, Sep 15, 2023 at 01:25:11PM -0700, Oza Pawandeep wrote:
> Arm® Functional Fixed Hardware Specification defines LPI states,
> which provide an architectural context loss flags field that can
> be used to describe the context that might be lost when an LPI
> state is entered.
> 
> - Core context Lost
>         - General purpose registers.
>         - Floating point and SIMD registers.
>         - System registers, include the System register based
>         - generic timer for the core.
>         - Debug register in the core power domain.
>         - PMU registers in the core power domain.
>         - Trace register in the core power domain.
> - Trace context loss
> - GICR
> - GICD
> 
> Qualcomm's custom CPUs preserves the architectural state,
> including keeping the power domain for local timers active.
> when core is power gated, the local timers are sufficient to
> wake the core up without needing broadcast timer.
> 
> The patch fixes the evaluation of cpuidle arch_flags, and moves only to
> broadcast timer if core context lost is defined in ACPI LPI.
> 
> Fixes: a36a7fecfe607 ("Add support for Low Power Idle(LPI) states")
> Reviewed-by: Sudeep Holla <sudeep.holla at arm.com>
> Signed-off-by: Oza Pawandeep <quic_poza at quicinc.com>
> ---
> 
> Notes:
>     Will/Catalin: Rafael has acked and he prefers to take it via arm64 tree

You need to add the tags received. You have added my review tag but not
the Rafael's Acked-by tag.

-- 
Regards,
Sudeep



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