Re: [PATCH v2] powercap: intel_rapl_tpmi: Handle PMU registration failure during probe

[Rafael J. Wysocki (Intel)]

On Sun, Jul 19, 2026 at 10:51 AM Sumeet Pawnikar <sumeet4linux@xxxxxxxxx> wrote:
>
> intel_rapl_tpmi_probe() invokes rapl_package_add_pmu() but ignores
> its return value, so a PMU registration failure would leave the driver
> reporting probe success despite the PMU being absent, with no log
> trace.
>
> Since PMU registration is an optional auxiliary feature for perf energy
> counters, its failure should not break the primary powercap functionality.
> Check the return value and log a warning to ensure graceful degradation.
>
> Fixes: 963a9ad3c589 ("powercap: intel_rapl_tpmi: Enable PMU support")
> Signed-off-by: Sumeet Pawnikar <sumeet4linux@xxxxxxxxx>
> ---
> v1->v2:
>   * Since PMU registration is an optional auxiliary feature here,
>     treat it's failure as a non fatal error and log a warning
>     and continue, similar to other RAPL drivers like intel_rapl_msr,
>     to ensure graceful degradation (Based on Sashiko feedback:
>     https://sashiko.dev/#/patchset/20260515184250.228062-1-sumeet4linux%40gmail.com)
>   * Add Fixes tag in changelog.
> ---
>  drivers/powercap/intel_rapl_tpmi.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/powercap/intel_rapl_tpmi.c b/drivers/powercap/intel_rapl_tpmi.c
> index 7f41491d9cd1..078a85158ce4 100644
> --- a/drivers/powercap/intel_rapl_tpmi.c
> +++ b/drivers/powercap/intel_rapl_tpmi.c
> @@ -414,7 +414,10 @@ static int intel_rapl_tpmi_probe(struct auxiliary_device *auxdev,
>                 goto err;
>         }
>
> -       rapl_package_add_pmu(trp->rp);
> +       ret = rapl_package_add_pmu(trp->rp);
> +       if (ret)
> +               dev_warn(&auxdev->dev, "Failed to add RAPL PMU for Package%d, %ld\n",
> +                       info->package_id, ret);

Please fix the format string as per the Sashiko comment at:

https://sashiko.dev/#/patchset/20260719085100.145555-1-sumeet4linux%40gmail.com

>         auxiliary_set_drvdata(auxdev, trp);
>
> --

Thanks!