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

-----Original Message-----
From: Will Deacon [mailto:will.deacon@arm.com]
Sent: 2014年10月20日 17:20
To: Sudeep Holla
Cc: Neil Zhang; 'linux@arm.linux.org.uk'; 'linux-arm-
kernel@lists.infradead.org'; 'linux-kernel@vger.kernel.org';
'devicetree@vger.kernel.org'; mathieu.poirier@linaro.org
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:

quoted

On 20/10/14 09:46, Neil Zhang wrote:

quoted

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