On Tue, Aug 30, 2016 at 06:32:25PM +0100, Mark Rutland wrote:

On Fri, Aug 26, 2016 at 10:48:00AM +0100, Will Deacon wrote:

quoted

On Fri, Aug 19, 2016 at 03:25:14PM +0100, Mark Rutland wrote:

quoted

On Thu, Aug 18, 2016 at 01:24:38PM -0700, Yabin Cui wrote:

quoted

   If the cpu pmu is using a percpu irq: ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
   ? ? ??
   1. When a cpu is down, we should disable pmu irq on ? ? ? ? ? ? ? ? ? ? ?
   that cpu. Otherwise, if the cpu is still down when ? ? ? ? ? ? ? ? ? ? ? ?
   the last perf event is released, the pmu irq can't ? ? ? ? ? ? ? ? ? ? ? ?
   be freed. Because the irq is still enabled on the ? ? ? ? ? ? ? ? ? ? ? ?
   offlined cpu. And following perf_event_open() ? ? ? ? ? ? ? ? ? ? ? ? ? ?
   syscalls will fail. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

   2. When a cpu is up, we should enable pmu irq on ? ? ? ? ? ? ? ? ? ? ? ? ?
   that cpu. Otherwise, profiling tools can't sample ? ? ? ? ? ? ? ? ? ? ? ?
   events on the cpu before all perf events are ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
   released, because pmu irq is disabled on that cpu. ? ? ? ? ? ? ? ? ? ? ? ?

[...]

quoted

quoted

Rather than adding more moving parts to the IRQ manipulation logic, I'd
rather we rework the IRQ manipulation logic to:

* At probe time, request all the interrupts. If we can't, bail out and
  fail the probe.

* Upon hotplug in (and at probe time), configure the affinity and
  enable the relevant interrupt(s).

* Upon hotplug out, disable the relevant interrupt.

quoted

quoted

I'm taking a look at doing the above, but I don't yet have a patch.

Any update on this? I'd quite like to do *something* to fix the issues
reported here.

Apologies for the delay.

I've been away from my development hardware for the last week, so I
ahven't fought with this for a few days.

Given it's requiring that I practically rewrite of_pmu_irq_cfg and
friends, it may be better to take Yabin's patch for the timebeing if you
want a quick fix for this particular issue.

Right, but that patch is totally mangled :/

I guess this will have to wait until somebody has time to rework the IRQ
code.

Will