Groups > linux.kernel > #1207349

Re: [PATCH v2 4/4] Added getsynctime64() callback

From	Richard Cochran <richardcochran@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 4/4] Added getsynctime64() callback
Date	2015-08-14 08:40 +0200
Message-ID	<pXgOJ-2xc-1@gated-at.bofh.it> (permalink)
References	<pUYVY-5Hg-13@gated-at.bofh.it> <pUYVY-5Hg-17@gated-at.bofh.it> <pVR62-15t-13@gated-at.bofh.it> <pX84N-6PO-11@gated-at.bofh.it>
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On Thu, Aug 13, 2015 at 09:10:36PM +0000, Hall, Christopher S wrote:
> > > +	if (!cpu_has_art)
> > > +		return -EOPNOTSUPP;
> > 
> > Perform this check before registration, setting .getsynctime64
> > accordingly.
> 
> The problem here is that ART initialization doesn't happen until we
> install TSC as a clocksource.  This design is per Thomas'
> suggestion.  That occurs after the driver is loaded (as a module).

So that 'cpu_has_art' actually means 'cpu_has_art_and_has_been_initialized'?

In any case, returning EOPNOTSUPP early on, but OK later seems mean to
me.  If the clocks aren't ready yet, the error should be EBUSY so that
user space knows it can try again.

Thanks,
Richard
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[PATCH v2 4/4] Added getsynctime64() callback Christopher Hall <christopher.s.hall@intel.com> - 2015-08-08 01:10 +0200
  Re: [PATCH v2 4/4] Added getsynctime64() callback Richard Cochran <richardcochran@gmail.com> - 2015-08-10 11:00 +0200
    RE: [PATCH v2 4/4] Added getsynctime64() callback "Hall, Christopher S" <christopher.s.hall@intel.com> - 2015-08-13 23:20 +0200
      Re: [PATCH v2 4/4] Added getsynctime64() callback Richard Cochran <richardcochran@gmail.com> - 2015-08-14 08:40 +0200

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