Messages in this thread | | | Date | Fri, 26 Jul 2019 16:18:25 +0100 | From | Lorenzo Pieralisi <> | Subject | Re: [PATCH] arm_pmu: Mark expected switch fall-through |
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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.roxell@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")
Yes that's correct, apologies. Probably we did not hit it because CPU PM notifier entry failures are a pretty rare event; regardless:
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
I can send the updated fix, just let me know.
Thanks, Lorenzo
> Thanks, > Mark. > > > > > drivers/perf/arm_pmu.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > > index 2d06b8095a19..465a15705bab 100644 > > --- a/drivers/perf/arm_pmu.c > > +++ b/drivers/perf/arm_pmu.c > > @@ -724,6 +724,7 @@ static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd, > > break; > > case CPU_PM_EXIT: > > cpu_pm_pmu_setup(armpmu, cmd); > > + /* Fall through */ > > case CPU_PM_ENTER_FAILED: > > armpmu->start(armpmu); > > break; > > -- > > 2.20.1 > >
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