RE: [PATCH v4] ARM: perf: save/restore pmu registers in pm notifier

[Neil Zhang]

> -----Original Message-----
> From: Will Deacon [mailto:will.deacon@xxxxxxx]
> Sent: 2014年10月20日 17:20
> To: Sudeep Holla
> Cc: Neil Zhang; 'linux@xxxxxxxxxxxxxxxx'; 'linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx'; 'linux-kernel@xxxxxxxxxxxxxxx';
> 'devicetree@xxxxxxxxxxxxxxx'; mathieu.poirier@xxxxxxxxxx
> Subject: Re: [PATCH v4] ARM: perf: save/restore pmu registers in pm
> notifier
> 
> On Mon, Oct 20, 2014 at 10:16:16AM +0100, Sudeep Holla wrote:
> > On 20/10/14 09:46, Neil Zhang wrote:
> > > Will, I prefer to check always-on field under PMU node to check
> > > whether we need Save/restore them.
> > >
> > But how do you handle it for different idle states. e.g. if CPU is in
> > retention, PMU's *might be* retained. Also I don't think PMUs will be
> > placed in "always-on" power domain like timers. So using "always-on"
> > sounds incorrect to me.
> 
> Adding Mathieu to CC, since I spoke to him at LPC about this and he was
> talking about implementing proper PM domain descriptions for coresight
> components.
> 

Good to know that!
Hope we can figure out it with a proper way.

> Will

Best Regards,
Neil Zhang