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    SubjectRe: [RFC][PATCH 0/14] Convert remaining arches to read/update_persistent_clock
    On Wed, Dec 23, 2009 at 06:08, Paul Mundt <> wrote:
    > On Tue, Dec 22, 2009 at 07:59:22PM -0800, john stultz wrote:
    >> In this case the generic read_persistent_clock() and
    >> update_persistent_clock() methods have been provided to allow the
    >> generic timekeeping code to initialize xtime and set the persistent
    >> clock when NTP is synced. However many arches haven't converted, so the
    >> generic code has to handle the case where the arch is doing this
    >> management itself.
    >> This patch series tries to convert the following 14 architectures over
    >> to use read_persistent_clock() and update_persistent_clock() as
    >> applicable, killing off about 200 lines of arch specific code.
    > While I think that this is a good goal, many of the underlying
    > architectures have veered pretty far away from having meaningful
    > persistent clock interfaces after having moved entirely to generic
    > timekeeping and the RTC subsystem.

    Indeed. When moving to the RTC subsystem, you loose the persistent
    clock at boot;
    i.e. on m68k, mach_hwclk() can no longer be set, as the RTC driver is
    in a separate
    (possible loadable) module.

    > In the case of SH at least that interface along with the generic CMOS
    > stuff is largely a stop-gap for antiquated platforms that don't have
    > proper RTC drivers and likely never will, while the default for all of
    > the rest of the platforms effectively returns a fixed dummy value. I
    > copied this approach from MIPS originally, so there are at least a few
    > architectures that this will apply to.
    > In any event, I wonder if it might make more sense to take something like
    > the SPARC implementation that is simply a wrapper around the RTC, move
    > that out in to a more generic place, and permit architectures to select
    > an RTC class backed persistent clock instead (it seems to be only
    > platforms that haven't caught up yet in terms of generic time and RTC
    > migration that would want to define this interface on their own at all at
    > this point)?

    Hmm, haven't looked into how SPARC handles this yet...
    Yes, looks like a good idea to me. Any disadvantages with this approach?



    Geert Uytterhoeven -- There's lots of Linux beyond ia32 --

    In personal conversations with technical people, I call myself a hacker. But
    when I'm talking to journalists I just say "programmer" or something like that.
    -- Linus Torvalds

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