> -----Original Message----- > From: Will Deacon [mailto:will.deacon@xxxxxxx] > Sent: 2014年4月24日 1:08 > To: Neil Zhang > Cc: linux@xxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; Sudeep Holla; devicetree@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v4] ARM: perf: save/restore pmu registers in pm notifier > > On Wed, Apr 23, 2014 at 11:31:09AM +0100, Neil Zhang wrote: > > > > > -----Original Message----- > > > From: Will Deacon [mailto:will.deacon@xxxxxxx] > > > Sent: 2014年4月22日 18:37 > > > To: Neil Zhang > > > Cc: linux@xxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > > linux-kernel@xxxxxxxxxxxxxxx; Sudeep Holla; > > > devicetree@xxxxxxxxxxxxxxx > > > Subject: Re: [PATCH v4] ARM: perf: save/restore pmu registers in pm > > > notifier > > > > > > Hi Neil, > > > > > > On Tue, Apr 22, 2014 at 03:26:36AM +0100, Neil Zhang wrote: > > > > This adds core support for saving and restoring CPU PMU registers > > > > for suspend/resume support i.e. deeper C-states in cpuidle terms. > > > > This patch adds support only to ARMv7 PMU registers save/restore. > > > > It needs to be extended to xscale and ARMv6 if needed. > > > > > > > > I made this patch because DS-5 is not working on Marvell's CA7 based > SoCs. > > > > And it has consulted Sudeep KarkadaNagesha's patch set for multiple > PMUs. > > > > > > > > Thanks Will and Sudeep's suggestion to only save / restore used events. > > > > > > Whilst this is a step in the right direction, I'd still like to see > > > the save/restore predicated on something in the device-tree or > > > otherwise. Most SoCs *don't* require these registers to be preserved > > > by software, so we need a way to describe that the PMU is in a > > > power-domain where its state is lost when the CPU goes idle. > > > > > > This doesn't sound like a PMU-specific problem, so there's a > > > possibility that this has been discussed elsewhere, in the context > > > of other IP blocks > > > > > > [adding the devicetree list in case somebody there is aware of any > > > work in this area] > > > > > > > Thanks Will. > > What should I do now? > > Add a filed under PMU or waiting for somebody whether there are > > general supporting for power domain maintain. > > I think we need some input from the device-tree guys to see whether they > would object to us solving this locally (in the PMU node) or not. > Personally, I'd much prefer a general way to describe the need for pm-notifiers, > but if that's not being looked at then we can cook something specifically for > our needs. > No input from device-tree guys :( > Will Best Regards, Neil Zhang ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
