Re: [PATCH] RTC: Add mmap method to rtc character driver

H. Peter Anvin
2006-07-26T00:04:42Z

Neil Horman wrote:
> On Wed, Jul 26, 2006 at 01:29:25AM +0200, Segher Boessenkool wrote:
>>> Yes, but if its in trade for something thats being used currently
>>> which hurts
>>> more (case in point being the X server), using this solution is a
>>> net gain.
>> ...in the short term.
>>
> And for any arch that isn't able to leverage a speedup via a vdso implementation
> of a simmilar functionality in the long term

If they can't, then they can't use your driver either.

>>> I'm not arguing with you that adding a low res gettimeofday
>>> vsyscall is a better
>>> long term solution, but doing that requires potentially several
>>> implementations
>>> in the C library accross a range of architectures, some of which
>>> may not be able
>>> to provide a time solution any better than what the gettimeofday
>>> syscall
>>> provides today. The /dev/rtc solution is easy, available right
>>> now, and applies
>>> to all arches.
>> "All"?
>>
> It there any arch for which the rtc driver doesn't function?

Yes, there are plenty of systems which don't have an RTC, or have an RTC
which can't generate interrupts.

-hpa