linux-kernel - Re: [PATCH v2] powerpc/powernv: Enable cpuidle state detection for POWER11

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Message-ID: <669f74ac-1d98-4d41-9237-a6385747743f@linux.ibm.com>
Date: Thu, 11 Dec 2025 11:24:40 +0530
From: Madadi Vineeth Reddy <vineethr@...ux.ibm.com>
To: Aboorva Devarajan <aboorvad@...ux.ibm.com>
Cc: maddy@...ux.ibm.com, linuxppc-dev@...ts.ozlabs.org, mahesh@...ux.ibm.com,
        mpe@...erman.id.au, npiggin@...il.com, christophe.leroy@...roup.eu,
        naveen@...nel.org, linux-kernel@...r.kernel.org,
        Madadi Vineeth Reddy <vineethr@...ux.ibm.com>
Subject: Re: [PATCH v2] powerpc/powernv: Enable cpuidle state detection for
 POWER11

Hi Aboorva,

On 08/09/25 14:21, Aboorva Devarajan wrote:
> Extend cpuidle state detection to POWER11 by updating the PVR check.
> This ensures POWER11 correctly recognizes supported stop states,
> similar to POWER9 and POWER10.
> 
> Without Patch: (Power11 - PowerNV systems)
> 
> CPUidle driver: powernv_idle
> CPUidle governor: menu
> analyzing CPU 927:
> 
> Number of idle states: 1
> Available idle states: snooze
> snooze:
> Flags/Description: snooze
> Latency: 0
> Usage: 251631
> Duration: 207497715900
> 
> --
> With Patch: (Power11 - PowerNV systems)
> 
> CPUidle driver: powernv_idle
> CPUidle governor: menu
> analyzing CPU 959:
> 
> Number of idle states: 4
> Available idle states: snooze stop0_lite stop0 stop3
> snooze:
> Flags/Description: snooze
> Latency: 0
> Usage: 2
> Duration: 33
> stop0_lite:
> Flags/Description: stop0_lite
> Latency: 1
> Usage: 1
> Duration: 52
> stop0:
> Flags/Description: stop0
> Latency: 10
> Usage: 13
> Duration: 1920
> stop3:
> Flags/Description: stop3
> Latency: 45
> Usage: 381
> Duration: 21638478

This patch enables correct recognition of P11 supported stop states.

Reviewed-by: Madadi Vineeth Reddy <vineethr@...ux.ibm.com>
Tested-by: Madadi Vineeth Reddy <vineethr@...ux.ibm.com>

Thanks,
Vineeth

> 
> Signed-off-by: Aboorva Devarajan <aboorvad@...ux.ibm.com>
> 
> ---
> 
> v1: https://lore.kernel.org/all/20250421070718.162783-1-aboorvad@linux.ibm.com/
> 
> v1 -> v2: Fixed overly permissive PVR version check as pointed out by
> Christophe.
> 
> ---
>  arch/powerpc/platforms/powernv/idle.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> index d98b933e4984..e4f4e907f6e3 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -1171,8 +1171,9 @@ static void __init pnv_arch300_idle_init(void)
>  	u64 max_residency_ns = 0;
>  	int i;
>  
> -	/* stop is not really architected, we only have p9,p10 drivers */
> -	if (!pvr_version_is(PVR_POWER10) && !pvr_version_is(PVR_POWER9))
> +	/* stop is not really architected, we only have p9,p10 and p11 drivers */
> +	if (!pvr_version_is(PVR_POWER9) && !pvr_version_is(PVR_POWER10) &&
> +		!pvr_version_is(PVR_POWER11))
>  		return;
>  
>  	/*
> @@ -1189,8 +1190,8 @@ static void __init pnv_arch300_idle_init(void)
>  		struct pnv_idle_states_t *state = &pnv_idle_states[i];
>  		u64 psscr_rl = state->psscr_val & PSSCR_RL_MASK;
>  
> -		/* No deep loss driver implemented for POWER10 yet */
> -		if (pvr_version_is(PVR_POWER10) &&
> +		/* No deep loss driver implemented for POWER10 and POWER11 yet */
> +		if ((pvr_version_is(PVR_POWER10) || pvr_version_is(PVR_POWER11)) &&
>  				state->flags & (OPAL_PM_TIMEBASE_STOP|OPAL_PM_LOSE_FULL_CONTEXT))
>  			continue;
>