linux-kernel - Re: [PATCH v6 4/4] platform/x86/intel/pmc: core: Report duration of time in HW sleep state

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Message-ID: <542ea1a76fda7cc45e8268697caaada4352f7dc2.camel@intel.com>
Date:   Wed, 5 Apr 2023 01:00:18 +0000
From:   "Box, David E" <david.e.box@...el.com>
To:     "jstultz@...gle.com" <jstultz@...gle.com>,
        "mario.limonciello@....com" <mario.limonciello@....com>,
        "svenva@...omium.org" <svenva@...omium.org>,
        "irenic.rajneesh@...il.com" <irenic.rajneesh@...il.com>
CC:     "Shyam-sundar.S-k@....com" <Shyam-sundar.S-k@....com>,
        "markgross@...nel.org" <markgross@...nel.org>,
        "rafael@...nel.org" <rafael@...nel.org>,
        "rrangel@...omium.org" <rrangel@...omium.org>,
        "Jain, Rajat" <rajatja@...gle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "hdegoede@...hat.com" <hdegoede@...hat.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>
Subject: Re: [PATCH v6 4/4] platform/x86/intel/pmc: core: Report duration of
 time in HW sleep state

On Mon, 2023-04-03 at 16:18 -0500, Mario Limonciello wrote:
> intel_pmc_core displays a warning when the module parameter
> `warn_on_s0ix_failures` is set and a suspend didn't get to a HW sleep
> state.
> 
> Report this to the standard kernel reporting infrastructure so that
> userspace software can query after the suspend cycle is done.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> v5->v6:
>  * Handle overflow case
>  * Use renamed symbol
> v4->v5:
>  * Reword commit message
> ---
>  drivers/platform/x86/intel/pmc/core.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core.c
> b/drivers/platform/x86/intel/pmc/core.c
> index 925c5d676a43..0621756792c8 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -1214,6 +1214,11 @@ static inline bool pmc_core_is_s0ix_failed(struct
> pmc_dev *pmcdev)
>         if (pmc_core_dev_state_get(pmcdev, &s0ix_counter))
>                 return false;
>  
> +       if (s0ix_counter >= pmcdev->s0ix_counter)
> +               pm_report_hw_sleep_time(s0ix_counter - pmcdev->s0ix_counter);

This would drop valid measurements when it's just the case that the counter has
overflowed but hasn't yet wrapped around to the previous value.

> +       else
> +               pm_report_hw_sleep_time(U64_MAX);


How about no if/else, just:

	return (u32)(s0ix_counter - pmcdev->s0ix_counter);

David

> +
>         if (s0ix_counter == pmcdev->s0ix_counter)
>                 return true;
>