linux-kernel - Re: [PATCH 3/3] pmdomain: core: Extend statistics for domain idle states with s2idle data

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Message-ID: <20260127135438.vkmcbpng6xb2adod@lcpd911>
Date: Tue, 27 Jan 2026 19:24:38 +0530
From: Dhruva Gole <d-gole@...com>
To: Ulf Hansson <ulf.hansson@...aro.org>
CC: <linux-pm@...r.kernel.org>, "Rafael J . Wysocki" <rafael@...nel.org>,
	Kevin Hilman <khilman@...libre.com>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] pmdomain: core: Extend statistics for domain idle
 states with s2idle data

On Jan 19, 2026 at 15:31:15 +0100, Ulf Hansson wrote:
> To allow user space to monitor the selection of the domain idle state
> during s2idle for a CPU PM domain, let's extend the debugfs support in
> genpd with this information.
> 
> Suggested-by: Dhruva Gole <d-gole@...com>
> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
> ---
>  drivers/pmdomain/core.c   | 13 ++++++++++---
>  include/linux/pm_domain.h |  1 +
>  2 files changed, 11 insertions(+), 3 deletions(-)

This will be quite helpful, thanks alot Ulf!
Reviewed-by: Dhruva Gole <d-gole@...com>

> 
> diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
> index bf512ff0857d..bb04cb7ccdcd 100644
> --- a/drivers/pmdomain/core.c
> +++ b/drivers/pmdomain/core.c
> @@ -1438,6 +1438,13 @@ static void genpd_sync_power_off(struct generic_pm_domain *genpd, bool use_lock,
>  		return;
>  	} else {
>  		genpd->states[genpd->state_idx].usage++;
> +
> +		/*
> +		 * The ->system_power_down_ok() callback is currently used only
> +		 * for s2idle. Use it to know when to update the usage counter.
> +		 */
> +		if (genpd->gov && genpd->gov->system_power_down_ok)
> +			genpd->states[genpd->state_idx].usage_s2idle++;
>  	}
>  
>  	genpd->status = GENPD_STATE_OFF;
> @@ -3772,7 +3779,7 @@ static int idle_states_show(struct seq_file *s, void *data)
>  	if (ret)
>  		return -ERESTARTSYS;
>  
> -	seq_puts(s, "State  Time(ms)       Usage      Rejected   Above      Below\n");
> +	seq_puts(s, "State  Time(ms)       Usage      Rejected   Above      Below      S2idle\n");
>  
>  	for (i = 0; i < genpd->state_count; i++) {
>  		struct genpd_power_state *state = &genpd->states[i];
> @@ -3790,9 +3797,9 @@ static int idle_states_show(struct seq_file *s, void *data)
>  
>  		snprintf(state_name, ARRAY_SIZE(state_name), "S%-5d", i);
>  		do_div(idle_time, NSEC_PER_MSEC);
> -		seq_printf(s, "%-6s %-14llu %-10llu %-10llu %-10llu %llu\n",
> +		seq_printf(s, "%-6s %-14llu %-10llu %-10llu %-10llu %-10llu %llu\n",
>  			   state_name, idle_time, state->usage, state->rejected,
> -			   state->above, state->below);
> +			   state->above, state->below, state->usage_s2idle);
>  	}
>  
>  	genpd_unlock(genpd);
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 93ba0143ca47..f6f6d494f728 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -183,6 +183,7 @@ struct genpd_power_state {
>  	u64 rejected;
>  	u64 above;
>  	u64 below;
> +	u64 usage_s2idle;
>  	struct fwnode_handle *fwnode;
>  	u64 idle_time;
>  	void *data;
> -- 
> 2.43.0
> 

-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated