Re: [PATCH v9 07/10] arm: arm64: pmu: Assign platform PMU CPU affinity

[Will Deacon <will.deacon@arm.com>]

On Fri, Sep 16, 2016 at 10:35:32AM -0500, Jeremy Linton wrote:
> On 09/16/2016 08:29 AM, Will Deacon wrote:
> >On Wed, Sep 14, 2016 at 05:32:35PM -0500, Jeremy Linton wrote:
> >>On systems with multiple PMU types the PMU to CPU affinity
> >>needs to be detected and set. The CPU to interrupt affinity
> >>should also be set.
> >>
> (trimming)
> >> 			continue;
> >> 		ret = info->init(pmu);
> >>+		/*
> >>+		 * if this pmu declaration is unspecified and we have
> >>+		 * previously found a PMU on this platform then append
> >>+		 * a PMU number to the pmu name. This avoids changing
> >>+		 * the names of PMUs that are specific to a class of CPUs.
> >>+		 * The assumption is that if we match a specific PMU in the
> >>+		 * provided pmu_probe_info then it's unique, and another PMU
> >>+		 * in the system will match a different entry rather than
> >>+		 * needing the _number to assure its unique.
> >>+		 */
> >>+		if ((!info->cpuid) && (duplicate_pmus)) {
> >
> >Hmm, the duplicate_pmus check looks a little odd here. Doesn't it mean
> >that you'd end up with things like:
> >
> >"arm,armv8-pmuv3"
> >"arm,armv8-pmuv3_1"
> >
> >which looks needlessly fiddly to parse. Is this intentional?
> 
> Well, IIRC, you recommend that format, or maybe I misunderstood. Anyway, per
> the comment I'm trying to assure that legacy platform devices don't
> accidentally get a "_X" appended to their name and break something.

Ah, right, for the old 32-bit platforms that rely on probing, Gotcha.

Will