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Subject: Re: [PATCH] RTC: Add mmap method to rtc character driver
From: Arjan van de Ven <arjan@infradead.org>
To: "John W. Linville" <linville@tuxdriver.com>
Cc: Neil Horman <nhorman@tuxdriver.com>, linux-kernel@vger.kernel.org,
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Date: Tue, 25 Jul 2006 21:16:02 +0200
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On Tue, 2006-07-25 at 15:07 -0400, John W. Linville wrote:
> On Tue, Jul 25, 2006 at 08:53:16PM +0200, Arjan van de Ven wrote:
> > On Tue, 2006-07-25 at 14:43 -0400, Neil Horman wrote:
> 
> > > alternative, which, as I mentioned before I would be happy to take a crack at,
> > > if you would elaborate on your idea a little more.
> > 
> > well the idea that has been tossed about a few times is using a vsyscall
> > function that either calls into the kernel, or directly uses the hpet
> > page (which can be user mapped) to get time information that way... 
> > or even would use rdtsc in a way the kernel knows is safe (eg corrected
> > for the local cpu's speed and offset etc etc).
> 
> Aren't both of those examples x86(_64)-specific?  Wouldn't a generic
> solution be preferrable?

the implementation is; the interface.. not so. other platforms can
implement their optimal solution obviously...