Messages in this thread Patch in this message | | | Date | Sat, 9 Jun 2018 22:21:06 +1000 (AEST) | From | Finn Thain <> | Subject | Re: [PATCH v2 08/12] macintosh/via-pmu68k: Don't load driver on unsupported hardware |
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> > > Is this enum used by any user space code? If so, perhaps rather > > > leave the PMU_68K_V1 in there to avoid upsetting that? > > > > It also changes the value of PMU_68K_V2, which is an ABI break. > > Yes, that's what I worry about - but do we know of any users of that > particular interface?
There is no ABI issue AFAIK. The value of pmu_kind is visible to userland only on powerpc. /dev/pmu and /proc/pmu/* do not exist on m68k. This patch series will make these UAPIs available on m68k, and for that reason I've chosen the value PMU_UNKNOWN for pmu_kind.
New pmu_kind values can be defined as and when the need arises. But that would imply a useful classification scheme for pre-PCI powerbooks, and I don't know what that scheme will look like because at this stage there is neither userland nor kernel code to support backlight, buttons and battery for pre-PCI powerbooks.
In anycase, the "v1" and "v2" scheme is obviously inadequate when you consider the range of m68k powerbook models. Also, consider the out-of-tree adaptation of via-pmu by the Nubus-PMac project, which has this ABI break:
diff --git a/include/linux/pmu.h b/include/linux/pmu.h index cafe98d9694..9882a185a52 100644 --- a/include/linux/pmu.h +++ b/include/linux/pmu.h @@ -90,6 +90,7 @@ enum { PMU_HEATHROW_BASED, /* PowerBook G3 series */ PMU_PADDINGTON_BASED, /* 1999 PowerBook G3 */ PMU_KEYLARGO_BASED, /* Core99 motherboard (PMU99) */ + PMU_NUBUS_BASED, /* 1400, 2300, 5300 */ PMU_68K_V1, /* 68K PMU, version 1 */ PMU_68K_V2, /* 68K PMU, version 2 */ }; (BTW, these powerbooks are not "nubus based", they are "pre-PCI", so I wouldn't want this to go upstream in this form. It could be that PMU_NUBUS_BASED should be PMU_UNKNOWN too.)
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