linux-kernel - Re: [PATCH v2 2/4] platform/x86: intel

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Date:   Thu, 23 Nov 2017 23:25:24 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Souvik Kumar Chakravarty <souvik.k.chakravarty@...el.com>
Cc:     Platform Driver <platform-driver-x86@...r.kernel.org>,
        "dvhart@...radead.org" <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Rajneesh Bhardwaj <rajneesh.bhardwaj@...el.com>
Subject: Re: [PATCH v2 2/4] platform/x86: intel_telemetry: Fix suspend stats

On Tue, Nov 21, 2017 at 4:36 PM, Souvik Kumar Chakravarty
<souvik.k.chakravarty@...el.com> wrote:
> Suspend stats are not reported consistently due to a limitation in the PMC
> firmware. This limitation causes a delay in updating the s0ix counters and
> residencies in the telemetry log upon s0ix exit. As a consequence, reading
> these counters from the suspend-exit notifier may result in zero read.
>
> This patch fixes this issue by cross-verifying the s0ix residencies from
> the GCR TELEM registers in case the counters are not incremented in the
> telemetry log after suspend.
>
> This fixes https://bugzilla.kernel.org/show_bug.cgi?id=197833
>
> We also remove unnecessary 'static' qualifiers from local variables.
>
> Reported-and-tested-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@...el.com>
> Signed-off-by: Souvik Kumar Chakravarty <souvik.k.chakravarty@...el.com>

> -       static u32 suspend_shlw_ctr_exit, suspend_deep_ctr_exit;
> -       static u64 suspend_shlw_res_exit, suspend_deep_res_exit;
>         struct telemetry_debugfs_conf *conf = debugfs_conf;
> +       u32 suspend_shlw_ctr_exit, suspend_deep_ctr_exit;
> +       u64 suspend_shlw_res_exit, suspend_deep_res_exit;
>         int ret, index;

> +       if (suspend_shlw_ctr_exit == suspend_shlw_ctr_temp &&
> +           suspend_deep_ctr_exit == suspend_deep_ctr_temp) {

kbuildbot is absolutely right. How this code is supposed to work? It's flaky.

Please, redesign this approach.

-- 
With Best Regards,
Andy Shevchenko