[PATCH V2 01/10] ARM: PMU: Add runtime PM Support

[Will Deacon]

Hi Jon,

Did you have any luck getting to the bottom of this?

It would be good to take your PMU suspend/resume patches once we know that
they will get used.

On Tue, Jun 12, 2012 at 11:41:27PM +0100, Jon Hunter wrote:
> On 06/12/2012 04:31 PM, Will Deacon wrote:
> > That's understandable -- one of the CPUs is likely more loaded than the
> > other. However, I'd like to confirm whether or not you see what I see. With
> > the 4430_init hack on a 4460, if I run:
> > 
> > # taskset 0x2 perf top
> > 
> > then I get no samples. If I do:
> > 
> > # taskset 0x1 perf top
> > 
> > then I *do* get samples and from *both* CPUs. So it smells more like an
> > issue poking some configuration registers from CPU1 rather than the IRQ
> > path being broken. As I said before, if I don't do the extra init hack
> > then I don't get this problem (but event counters don't tick).
> 
> In both cases, I see interrupts on both CPUs. However, typically more on
> the CPU that perf is running on (which is probably to be expected). And
> I confirm that the only change I made was ...

[...]

> When you boot the kernel what 4460 rev does it show (very early in the
> kernel boot log)? Mine shows ...
> 
> [    0.000000] OMAP4460 ES1.1

Snap: [    0.000000] OMAP4460 ES1.1

> However, the A9 version has not changed between ES1.0 and ES1.1. Both
> should be r2p10.

Yup, that's what /proc/cpuinfo says.

Will