linux-kernel - Re: [PATCH v7] cpuidle, ACPI: Evaluate LPI arch

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Message-ID: <20230918105221.msuwbo2deya6rdim@bogus>
Date:   Mon, 18 Sep 2023 11:52:21 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Oza Pawandeep <quic_poza@...cinc.com>
Cc:     catalin.marinas@....com, will@...nel.org, rafael@...nel.org,
        lenb@...nel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH v7] cpuidle, ACPI: Evaluate LPI arch_flags for broadcast
 timer

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@....com>
> Signed-off-by: Oza Pawandeep <quic_poza@...cinc.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