On Fri, Jul 26, 2019 at 01:29:56PM +0100, Mark Rutland wrote:
> On Fri, Jul 26, 2019 at 01:27:37PM +0200, Anders Roxell wrote:
> > When fall-through warnings was enabled by default the following warning
> > was starting to show up:
> >
> > ../drivers/perf/arm_pmu.c: In function ‘cpu_pm_pmu_notify’:
> > ../drivers/perf/arm_pmu.c:726:3: warning: this statement may fall
> > through [-Wimplicit-fallthrough=]
> > cpu_pm_pmu_setup(armpmu, cmd);
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > ../drivers/perf/arm_pmu.c:727:2: note: here
> > case CPU_PM_ENTER_FAILED:
> > ^~~~
> >
> > Rework so that the compiler doesn't warn about fall-through.
> >
> > Fixes: d93512ef0f0e ("Makefile: Globally enable fall-through warning")
> > Signed-off-by: Anders Roxell <anders.rox...@linaro.org>
> > ---
> >
> > I'm not convinced that this is the correct patch to fix this issue.
> > However, I can't see why we do 'armpmu->start(armpmu);' only in 'case
> > CPU_PM_ENTER_FAILED' and why we not call function cpu_pm_pmu_setup()
> > there also, since in cpu_pm_pmu_setup() has a case prepared for
> > CPU_PM_ENTER_FAILED.
>
> I agree, think that should be:
>
> case CPU_PM_EXIT:
> case CPU_PM_ENTER_FAILED:
> cpu_pm_pmu_setup(armpmu, cmd);
> armpmu->start(armpmu);
> break;
>
> ... so that we re-start the events before we start the PMU.
>
> That would be a fix for commit:
>
> da4e4f18afe0f372 ("drivers/perf: arm_pmu: implement CPU_PM notifier")
Does seem about right, but I'd like Lorenzo's ack on this.
Will
