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

Arjan van de Ven
2006-07-25T19:16:06Z

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...