oprofile and ARM A9 hardware counter

[Shilimkar, Santosh]

On Tue, Apr 3, 2012 at 6:04 PM, Will Deacon <will.deacon at arm.com> wrote:
> On Tue, Apr 03, 2012 at 11:01:53AM +0100, Shilimkar, Santosh wrote:
>> On Tue, Apr 3, 2012 at 3:17 PM, Will Deacon <will.deacon at arm.com> wrote:
>> > It seems that they're both needed to get reliable PMU operation. Without the
>> > CLKDM_CAN_SWSUP fix, no interrupts are generated at all. Without the patch
>> > below ([1]), it seems that we don't generate enough. So it looks like we
>> > need them both.
>> >
>> I see. Can you please confirm if it is still the case with [1].
>
> Right, ignore my previous comment, I was using a vanilla 3.3 kernel without
> realising and therefore what I thought were PMU/CTI interrupts were actually
> just from a timer. Sorry for the confusion.
>
> So I've gone back to basics. Here is a branch containing what I believe
> should be all the patches required for the OMAP4 PMU:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git perf/omap4
>
> I've omitted the SWSUSP patch since you say it breaks pm, which is clearly not
> acceptable.
>
> The problem is, trying to boot this on my pandaboard results in a hang (see
> dmesg below). Even worse, the problem isn't easily bisectable since rebuilding
> a working image can give you something that no longer boots and I haven't found
> a reliable way to cause the lockup.
>
> I'll take JTAG for a whirl to see where we are. If anything looks wrong in
> my dmesg, please shout (there are plenty of things in there that look like
> they've gone awry).
>
I don't see anything abnormal in below boot log. Not sure why it
hands around there.

Regards
Santosh