linux-kernel - Re: [PATCH v1] platform/x86: intel_pmc_core: promote S0ix failure warn() to WARN()

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Message-ID: <4b7304c0-8dd5-9add-7c84-4e9f0aa9396b@redhat.com>
Date:   Thu, 27 Oct 2022 17:40:36 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Sven van Ashbrook <svenva@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     platform-driver-x86@...r.kernel.org,
        Rajneesh Bhardwaj <rajneesh.bhardwaj@...el.com>,
        Rafael J Wysocki <rjw@...ysocki.net>,
        Rajat Jain <rajatja@...gle.com>,
        David E Box <david.e.box@...el.com>,
        Mark Gross <markgross@...nel.org>,
        Rajneesh Bhardwaj <irenic.rajneesh@...il.com>
Subject: Re: [PATCH v1] platform/x86: intel_pmc_core: promote S0ix failure
 warn() to WARN()

Hi,

On 10/27/22 17:19, Sven van Ashbrook wrote:
> The "failure to enter S0ix" warning is critically important for monitoring
> and debugging power regressions, both in the field and in the test lab.
> 
> Promote from lower-case warn() to upper-case WARN() so that it becomes
> more prominent, and gets picked up as part of existing monitoring
> infrastructure, which typically focuses on WARN() and ignores warn()
> type log messages.
> 
> Signed-off-by: Sven van Ashbrook <svenva@...omium.org>

WARN() is really only intended for internal kernel bugs and not for
hw misbehaving, so I'm not a fan of the change you are suggesting here.

Intel folks, do you have an opinion on this ?

Regards,

Hans


> ---
> Against v6.1-rc2
> 
>  drivers/platform/x86/intel/pmc/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index a1fe1e0dcf4a5..834f0352c0edf 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -2125,7 +2125,7 @@ static __maybe_unused int pmc_core_resume(struct device *dev)
>  	}
>  
>  	/* The real interesting case - S0ix failed - lets ask PMC why. */
> -	dev_warn(dev, "CPU did not enter SLP_S0!!! (S0ix cnt=%llu)\n",
> +	dev_WARN(dev, "CPU did not enter SLP_S0!!! (S0ix cnt=%llu)\n",
>  		 pmcdev->s0ix_counter);
>  	if (pmcdev->map->slps0_dbg_maps)
>  		pmc_core_slps0_display(pmcdev, dev, NULL);