Messages in this thread | | | Date | Mon, 20 Oct 2014 10:16:16 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH v4] ARM: perf: save/restore pmu registers in pm notifier |
| |
Hi Neil,
On 20/10/14 09:46, Neil Zhang wrote: > > >> -----Original Message----- From: Will Deacon >> [mailto:will.deacon@arm.com] Sent: 2014年7月4日 1:57 To: Neil Zhang >> Cc: Sudeep Holla; 'linux@arm.linux.org.uk'; 'linux-arm- >> kernel@lists.infradead.org'; 'linux-kernel@vger.kernel.org'; >> 'devicetree@vger.kernel.org' Subject: Re: [PATCH v4] ARM: perf: >> save/restore pmu registers in pm notifier >> >> On Mon, Jun 30, 2014 at 11:39:15AM +0100, Neil Zhang wrote: >>>>>> I will prepare another patch to add DT description under >>>>>> PMU since there is no generic power domain support for pm >>>>>> notifier if no other concerns. We can change the manner if >>>>>> there is generic power domain support for pm notifier >>>>>> later. Thanks. >>>>> >>>>> No, please don't add any DT bindings for power domains >>>>> specific to PMU node. We can't change the DT bindings once >>>>> added. >>>>> >>>>> As I pointed out the DT bindings for generic power domains >>>>> are under discussion. See if you can reuse it, if not help in >>>>> extending it so that it can be used. >>>>> >>>> Sorry for reply later. As I said before the under discussed >>>> generic power domain is not suitable for CPU peripherals since >>>> they are all known belong to CPU or cluster power domain. If >>>> we want to follow the way they are discussion, we need to >>>> register core and cluster power provider, and need vfp/gic/pmu >>>> etc to require them. >>>> Is it really suitable? >>>> >>> Do you have any comments? If no, I would like to put it under PMU >>> node. >> >> Sudeep is a better person to comment than me, but I'd still rather >> this was handled more generically as opposed to a PMU-specific >> hack. I don't see a problem including GIC and VFP here, but only >> when we actually need to save/restore them (i.e. what the hardware >> guys went crazy with the power domains). >> > > Long time no follow up for this loop. Sorry that I will pick it > again. > Yes, the generic PD got added in v3.18-rc1, it's better to check if we can reuse it. I will also have a look at that and think about how we can use it.
> 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.
Regards, Sudeep
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |