On Thu, May 30, 2013 at 7:36 AM, Andy Green <andy.gr...@linaro.org> wrote:
> Hi -
>
> We're using one kernel binary with BL Switcher enabled in config, but able
> to work on SoC without Big Little.
>
> This is OK except where the BL patches touch the PMU driver. It makes an
> assumption about BL configured == in use which is not true. PMU init fails
> and when you try to use perf list later, it blows chunks.
>
> I worked around it with the hack below, so it can fail out from the
> bigLITTLE path when it doesn't see the cluster property in DT, but there's
> presumably a better way to do that which more directly checks if we care
> about BL in this execution environment.
>
> -Andy
>
This is Dave's area but Nico ought to weigh in whether the presence of
the DT property is the best place for this. It seems OK to me.
>
> Author: Andy Green <andy.gr...@linaro.org>
> Date: Thu May 30 09:44:17 2013 +0800
>
> bl switcher fix dont assume bl active in pmu probe
>
> Signed-off-by: Andy Green <andy.gr...@linaro.org>
>
> diff --git a/arch/arm/kernel/perf_event_cpu.c
> b/arch/arm/kernel/perf_event_cpu.c
> index b3ae24f..c02ea21 100644
> --- a/arch/arm/kernel/perf_event_cpu.c
> +++ b/arch/arm/kernel/perf_event_cpu.c
> @@ -440,6 +440,9 @@ static int cpu_pmu_device_probe(struct platform_device
> *pdev)
> hwid = of_get_property(ncluster, "reg", &len);
> if (hwid && len == 4)
> cluster = be32_to_cpup(hwid);
> + } else {
> + ret = probe_current_pmu(pmu);
> + goto bail;
> }
> /* set sibling mask to all cpu mask if socket is not
> specified */
> /*
> @@ -501,7 +504,7 @@ static int cpu_pmu_device_probe(struct platform_device
> *pdev)
> } else {
> ret = probe_current_pmu(pmu);
> }
> -
> +bail:
> if (ret)
> goto error;
>
>
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