oprofile and ARM A9 hardware counter

[Shilimkar, Santosh]

On Tue, Apr 3, 2012 at 3:17 PM, Will Deacon <will.deacon at arm.com> wrote:
> On Tue, Apr 03, 2012 at 10:42:30AM +0100, Shilimkar, Santosh wrote:
>> On Tue, Apr 3, 2012 at 2:55 PM, Will Deacon <will.deacon at arm.com> wrote:
>> > Did you ever get to the bottom of this? This change really is required in
>> > order to generate PMU interrupts with the CTI and I don't know of any
>> > alternative to the above.
>> >
>> > Any suggestions?
>> >
>> Sorry I lost track of this one. There is one relevant patch in Kevin's queue
>> for 3.4/fixes. [1] which I generated for perf time stamp issue.
>
> Thanks, I'll take a look.
>
>> Can you try that patch and see if it helps the CTI issue as well ? There
>> is an outside chance that it might help. If it doesn't, we should commit
>> Ming Lei  patch.
>
> 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].

If yes then am nou sure how to proceed. because permanently setting
EMU CD to CLKDM_CAN_SWSUP will break PM.

>> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2012-March/089679.html
>