linux-kernel - Re: [PATCH 4/4] intel_idle: Add SPR support with AMX INIT-state

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Message-ID: <0B7F49C0-B850-45BC-BEC9-60DF3E2D88C5@intel.com>
Date:   Fri, 5 Nov 2021 16:03:56 +0000
From:   "Bae, Chang Seok" <chang.seok.bae@...el.com>
To:     Thomas Gleixner <tglx@...utronix.de>
CC:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "bp@...en8.de" <bp@...en8.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 4/4] intel_idle: Add SPR support with AMX INIT-state

On Nov 5, 2021, at 07:33, Thomas Gleixner <tglx@...utronix.de> wrote:
> 
> Chang,
> 
> On Thu, Nov 04 2021 at 15:52, Chang S. Bae wrote:
>> +/**
>> + * intel_idle_tile - Ask the processor to enter the given idle state.
>> + * @dev: cpuidle device of the target CPU.
>> + * @drv: cpuidle driver (assumed to point to intel_idle_driver).
>> + *
>> + * Ensure TILE registers in INIT-state before using intel_idle() to
>> + * enter the idle state.
>> + */
>> +static __cpuidle int intel_idle_tile(struct cpuidle_device *dev,
>> +				     struct cpuidle_driver *drv, int index)
>> +{
>> +	fpu_idle_fpregs();
> 
> That's redundant because arch_cpu_idle_enter() is invoked before the
> actual idle mechanism. 

I think the way this series is shaped makes confusion, sorry.

Since PATCH3 and PATCH4 are in debate -- which approach should be chosen, it
was decided to post both and let just one of them be selected. E.g., if PATCH3
is right, then PATCH4 should be abandoned.

I think PATCH3 is better. Maybe PATCH4 should not be sent together to avoid
such confusion.

Thanks,
Chang